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151-439: Platinum is a chemical element ; it has symbol Pt and atomic number 78. It is a dense , malleable , ductile , highly unreactive, precious , silverish-white transition metal . Its name originates from Spanish platina , a diminutive of plata "little silver". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements . It has six naturally occurring isotopes . It
302-548: A platinized platinum electrode due to its corrosion resistance, and other attributes. Platinum is a precious metal commodity ; its bullion has the ISO currency code of XPT. Coins, bars, and ingots are traded or collected. Platinum finds use in jewellery, usually as a 90–95% alloy, due to its inertness. It is used for this purpose for its prestige and inherent bullion value. Jewellery trade publications advise jewellers to present minute surface scratches (which they term patina ) as
453-738: A pure element . In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the same atomic number, or number of protons . Nuclear scientists, however, define a pure element as one that consists of only one isotope. For example, a copper wire is 99.99% chemically pure if 99.99% of its atoms are copper, with 29 protons each. However it is not isotopically pure since ordinary copper consists of two stable isotopes, 69% Cu and 31% Cu, with different numbers of neutrons. However, pure gold would be both chemically and isotopically pure, since ordinary gold consists only of one isotope, Au. Atoms of chemically pure elements may bond to each other chemically in more than one way, allowing
604-805: A British metallurgist , found various samples of Colombian platinum in Jamaica, which he sent to William Brownrigg for further investigation. In 1750, after studying the platinum sent to him by Wood, Brownrigg presented a detailed account of the metal to the Royal Society , stating that he had seen no mention of it in any previous accounts of known minerals. Brownrigg also made note of platinum's extremely high melting point and refractoriness toward borax . Other chemists across Europe soon began studying platinum, including Andreas Sigismund Marggraf , Torbern Bergman , Jöns Jakob Berzelius , William Lewis , and Pierre Macquer . In 1752, Henrik Scheffer published
755-472: A component of bad breath odor. Not all organic sulfur compounds smell unpleasant at all concentrations: the sulfur-containing monoterpenoid grapefruit mercaptan in small concentrations is the characteristic scent of grapefruit, but has a generic thiol odor at larger concentrations. Sulfur mustard , a potent vesicant , was used in World War ;I as a disabling agent. Sulfur–sulfur bonds are
906-419: A conductor, its demand is not so driven by industrial uses. In the 18th century, platinum's rarity made King Louis XV of France declare it the only metal fit for a king. In the laboratory, platinum wire is used for electrodes; platinum pans and supports are used in thermogravimetric analysis because of the stringent requirements of chemical inertness upon heating to high temperatures (~1000 °C). Platinum
1057-549: A considerable amount of time. (See element naming controversy ). Precursors of such controversies involved the nationalistic namings of elements in the late 19th century. For example, lutetium was named in reference to Paris, France. The Germans were reluctant to relinquish naming rights to the French, often calling it cassiopeium . Similarly, the British discoverer of niobium originally named it columbium , in reference to
1208-471: A dark-red transparent crystalline compound has been shown to contain Pt anions. Platinum also exhibits negative oxidation states at surfaces reduced electrochemically. The negative oxidation states exhibited by platinum are unusual for metallic elements, and they are attributed to the relativistic stabilization of the 6s orbitals. It is predicted that even the cation PtO 4 in which platinum exists in
1359-434: A desirable feature in an attempt to enhance value of platinum products. In watchmaking , Vacheron Constantin , Patek Philippe , Rolex , Breitling , and other companies use platinum for producing their limited edition watch series. Watchmakers appreciate the unique properties of platinum, as it neither tarnishes nor wears out (the latter quality relative to gold). During periods of sustained economic stability and growth,
1510-426: A detailed scientific description of the metal, which he referred to as "white gold", including an account of how he succeeded in fusing platinum ore with the aid of arsenic . Scheffer described platinum as being less pliable than gold, but with similar resistance to corrosion. Karl von Sickingen researched platinum extensively in 1772. He succeeded in making malleable platinum by alloying it with gold, dissolving
1661-477: A different element in nuclear reactions , which change an atom's atomic number. Historically, the term "chemical element" meant a substance that cannot be broken down into constituent substances by chemical reactions, and for most practical purposes this definition still has validity. There was some controversy in the 1920s over whether isotopes deserved to be recognized as separate elements if they could be separated by chemical means. The term "(chemical) element"
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#17327649443811812-652: A few decay products, to have been differentiated from other elements. Most recently, the synthesis of element 118 (since named oganesson ) was reported in October 2006, and the synthesis of element 117 ( tennessine ) was reported in April 2010. Of these 118 elements, 94 occur naturally on Earth. Six of these occur in extreme trace quantities: technetium , atomic number 43; promethium , number 61; astatine , number 85; francium , number 87; neptunium , number 93; and plutonium , number 94. These 94 elements have been detected in
1963-529: A few elements, such as silver and gold , are found uncombined as relatively pure native element minerals . Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. Air is mostly a mixture of molecular nitrogen and oxygen , though it does contain compounds including carbon dioxide and water , as well as atomic argon , a noble gas which is chemically inert and therefore does not undergo chemical reactions. The history of
2114-484: A liquid. Platinum is paramagnetic , whereas nickel and iron are both ferromagnetic . These two impurities are thus removed by running an electromagnet over the mixture. Because platinum has a higher melting point than most other substances, many impurities can be burned or melted away without melting the platinum. Finally, platinum is resistant to hydrochloric and sulfuric acids, whereas other substances are readily attacked by them. Metal impurities can be removed by stirring
2265-587: A major industrial product, especially in automobile tires. Because of the heat and sulfur, the process was named vulcanization , after the Roman god of the forge and volcanism . Being abundantly available in native form, sulfur was known in ancient times and is referred to in the Torah ( Genesis ). English translations of the Christian Bible commonly referred to burning sulfur as "brimstone", giving rise to
2416-407: A platinum-iridium (90:10) alloy bar, known as the international prototype meter . The previous bar was made of platinum in 1799. Until May 2019, the kilogram was defined as the mass of the international prototype of the kilogram , a cylinder of the same platinum-iridium alloy made in 1879. The Standard Platinum Resistance Thermometer (SPRT) is one of the four types of thermometers used to define
2567-500: A pressure of 1 bar and a given temperature (typically at 298.15K). However, for phosphorus, the reference state is white phosphorus even though it is not the most stable allotrope, and the reference state for carbon is graphite, because the structure of graphite is more stable than that of the other allotropes. In thermochemistry , an element is defined to have an enthalpy of formation of zero in its reference state. Several kinds of descriptive categorizations can be applied broadly to
2718-483: A pressure of one atmosphere, are commonly used in characterizing the various elements. While known for most elements, either or both of these measurements is still undetermined for some of the radioactive elements available in only tiny quantities. Since helium remains a liquid even at absolute zero at atmospheric pressure, it has only a boiling point, and not a melting point, in conventional presentations. The density at selected standard temperature and pressure (STP)
2869-456: A small group, (the metalloids ), having intermediate properties and often behaving as semiconductors . A more refined classification is often shown in colored presentations of the periodic table. This system restricts the terms "metal" and "nonmetal" to only certain of the more broadly defined metals and nonmetals, adding additional terms for certain sets of the more broadly viewed metals and nonmetals. The version of this classification used in
3020-416: A structural component used to stiffen rubber, similar to the disulfide bridges that rigidify proteins (see biological below). In the most common type of industrial "curing" or hardening and strengthening of natural rubber , elemental sulfur is heated with the rubber to the point that chemical reactions form disulfide bridges between isoprene units of the polymer. This process, patented in 1843, made rubber
3171-412: A thin surface film of PtO 2 that can be easily removed by heating to about 400 °C. The most common oxidation states of platinum are +2 and +4. The +1 and +3 oxidation states are less common, and are often stabilized by metal bonding in bimetallic (or polymetallic) species. Tetracoordinate platinum(II) compounds tend to adopt 16-electron square planar geometries. Although elemental platinum
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#17327649443813322-433: A tracer in hydrologic studies. Differences in the natural abundances can be used in systems where there is sufficient variation in the S of ecosystem components. Rocky Mountain lakes thought to be dominated by atmospheric sources of sulfate have been found to have measurably different S values than lakes believed to be dominated by watershed sources of sulfate. The radioactive S is formed in cosmic ray spallation of
3473-474: A whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than ~1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of
3624-457: A wide variety of cancers, including testicular and ovarian carcinomas, melanoma, small-cell and non-small-cell lung cancer, myelomas and lymphomas. Chemical element A chemical element is a chemical substance whose atoms all have the same number of protons . The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus. Atoms of
3775-455: Is Pt , comprising 33.83% of all platinum. It is the only stable isotope with a non-zero spin . The spin of / 2 and other favourable magnetic properties of the nucleus are utilised in Pt NMR . Due to its spin and large abundance, Pt satellite peaks are also often observed in H and P NMR spectroscopy ( e.g., for Pt-phosphine and Pt-alkyl complexes). Pt
3926-404: Is 10 (for tin , element 50). The mass number of an element, A , is the number of nucleons (protons and neutrons) in the atomic nucleus. Different isotopes of a given element are distinguished by their mass number, which is written as a superscript on the left hand side of the chemical symbol (e.g., U). The mass number is always an integer and has units of "nucleons". Thus, magnesium-24 (24
4077-566: Is a chemical element ; it has symbol S and atomic number 16. It is abundant , multivalent and nonmetallic . Under normal conditions , sulfur atoms form cyclic octatomic molecules with the chemical formula S 8 . Elemental sulfur is a bright yellow, crystalline solid at room temperature . Sulfur is the tenth most abundant element by mass in the universe and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals . Being abundant in native form, sulfur
4228-606: Is a mixture of C (about 98.9%), C (about 1.1%) and about 1 atom per trillion of C. Most (54 of 94) naturally occurring elements have more than one stable isotope. Except for the isotopes of hydrogen (which differ greatly from each other in relative mass—enough to cause chemical effects), the isotopes of a given element are chemically nearly indistinguishable. All elements have radioactive isotopes (radioisotopes); most of these radioisotopes do not occur naturally. Radioisotopes typically decay into other elements via alpha decay , beta decay , or inverse beta decay ; some isotopes of
4379-465: Is a common reagent in organic synthesis . Bromine also oxidizes sulfur to form sulfur dibromide and disulfur dibromide . Sulfur oxidizes cyanide and sulfite to give thiocyanate and thiosulfate , respectively. Sulfur reacts with many metals. Electropositive metals give polysulfide salts. Copper, zinc, and silver are attacked by sulfur; see tarnishing . Although many metal sulfides are known, most are prepared by high temperature reactions of
4530-406: Is a dimensionless number equal to the atomic mass divided by the atomic mass constant , which equals 1 Da. In general, the mass number of a given nuclide differs in value slightly from its relative atomic mass, since the mass of each proton and neutron is not exactly 1 Da; since the electrons contribute a lesser share to the atomic mass as neutron number exceeds proton number; and because of
4681-501: Is a lustrous, ductile , and malleable , silver-white metal. Platinum is more ductile than gold , silver or copper , thus being the most ductile of pure metals, but it is less malleable than gold. Its physical characteristics and chemical stability make it useful for industrial applications. Its resistance to wear and tarnish is well suited to use in fine jewellery . Platinum has excellent resistance to corrosion . Bulk platinum does not oxidize in air at any temperature, but it forms
Platinum - Misplaced Pages Continue
4832-443: Is a major precious metal commodity . Platinum is one of the least reactive metals . It has remarkable resistance to corrosion , even at high temperatures, and is therefore considered a noble metal . Consequently, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the alluvial sands of various rivers, it was first used by pre-Columbian South American natives to produce artifacts. It
4983-579: Is a major source of platinum associated with nickel ores in the Sudbury Basin deposit in Ontario , Canada . At Platinum, Alaska , about 17,000 kg (550,000 ozt) was mined between 1927 and 1975. The mine ceased operations in 1990. The rare sulfide mineral cooperite , (Pt,Pd,Ni)S , contains platinum along with palladium and nickel. Cooperite occurs in the Merensky Reef within
5134-511: Is a soft, bright-yellow solid that is odorless. It melts at 115.21 °C (239.38 °F), and boils at 444.6 °C (832.3 °F). At 95.2 °C (203.4 °F), below its melting temperature, cyclo-octasulfur begins slowly changing from α-octasulfur to the β- polymorph . The structure of the S 8 ring is virtually unchanged by this phase transition, which affects the intermolecular interactions. Cooling molten sulfur freezes at 119.6 °C (247.3 °F), as it predominantly consists of
5285-424: Is a strong oxidizer capable of oxidizing oxygen . Platinum(IV) oxide , PtO 2 , also known as " Adams' catalyst ", is a black powder that is soluble in potassium hydroxide (KOH) solutions and concentrated acids. PtO 2 and the less common PtO both decompose upon heating. Platinum(II,IV) oxide, Pt 3 O 4 , is formed in the following reaction: Unlike palladium acetate , platinum(II) acetate
5436-599: Is about 2 g/cm , depending on the allotrope; all of the stable allotropes are excellent electrical insulators. Sulfur sublimes more or less between 20 °C (68 °F) and 50 °C (122 °F). Sulfur is insoluble in water but soluble in carbon disulfide and, to a lesser extent, in other nonpolar organic solvents, such as benzene and toluene . Under normal conditions, sulfur hydrolyzes very slowly to mainly form hydrogen sulfide and sulfuric acid : The reaction involves adsorption of protons onto S 8 clusters, followed by disproportionation into
5587-447: Is also used in the petroleum industry as a catalyst in a number of separate processes, but especially in catalytic reforming of straight-run naphthas into higher-octane gasoline that becomes rich in aromatic compounds. PtO 2 , also known as Adams' catalyst , is used as a hydrogenation catalyst, specifically for vegetable oils . Platinum also strongly catalyzes the decomposition of hydrogen peroxide into water and oxygen and it
5738-484: Is an essential element for all life, almost always in the form of organosulfur compounds or metal sulfides. Amino acids (two proteinogenic : cysteine and methionine , and many other non-coded : cystine , taurine , etc.) and two vitamins ( biotin and thiamine ) are organosulfur compounds crucial for life. Many cofactors also contain sulfur, including glutathione , and iron–sulfur proteins . Disulfides , S–S bonds, confer mechanical strength and insolubility of
5889-405: Is an extremely rare metal, occurring at a concentration of only 0.005 ppm in Earth's crust . Sometimes mistaken for silver, platinum is often found chemically uncombined as native platinum and as alloy with the other platinum-group metals and iron mostly. Most often the native platinum is found in secondary deposits in alluvial deposits. The alluvial deposits used by pre-Columbian people in
6040-812: Is an ongoing area of scientific study. The lightest elements are hydrogen and helium , both created by Big Bang nucleosynthesis in the first 20 minutes of the universe in a ratio of around 3:1 by mass (or 12:1 by number of atoms), along with tiny traces of the next two elements, lithium and beryllium . Almost all other elements found in nature were made by various natural methods of nucleosynthesis . On Earth, small amounts of new atoms are naturally produced in nucleogenic reactions, or in cosmogenic processes, such as cosmic ray spallation . New atoms are also naturally produced on Earth as radiogenic daughter isotopes of ongoing radioactive decay processes such as alpha decay , beta decay , spontaneous fission , cluster decay , and other rarer modes of decay. Of
6191-425: Is as a catalyst in chemical reactions, often as platinum black . It has been employed as a catalyst since the early 19th century, when platinum powder was used to catalyze the ignition of hydrogen. Its most important application is in automobiles as a catalytic converter , which allows the complete combustion of low concentrations of unburned hydrocarbons from the exhaust into carbon dioxide and water vapor. Platinum
Platinum - Misplaced Pages Continue
6342-460: Is based on a Latin or other traditional word, for example adopting "gold" rather than "aurum" as the name for the 79th element (Au). IUPAC prefers the British spellings " aluminium " and "caesium" over the U.S. spellings "aluminum" and "cesium", and the U.S. "sulfur" over British "sulphur". However, elements that are practical to sell in bulk in many countries often still have locally used national names, and countries whose national language does not use
6493-417: Is explained by its production in the so-called alpha-process (one of the main classes of nuclear fusion reactions) in exploding stars. Other stable sulfur isotopes are produced in the bypass processes related with Ar, and their composition depends on a type of a stellar explosion. For example, proportionally more S comes from novae than from supernovae . On the planet Earth the sulfur isotopic composition
6644-408: Is generally unreactive, it is attacked by chlorine , bromine , iodine , and sulfur . It reacts vigorously with fluorine at 500 °C (932 °F) to form platinum tetrafluoride . Platinum is insoluble in hydrochloric and nitric acid , but dissolves in hot aqua regia (a mixture of nitric and hydrochloric acids), to form aqueous chloroplatinic acid , H 2 PtCl 6 : As a soft acid ,
6795-468: Is higher than the melting point of sulfur. Native sulfur is synthesized by anaerobic bacteria acting on sulfate minerals such as gypsum in salt domes . Significant deposits in salt domes occur along the coast of the Gulf of Mexico , and in evaporites in eastern Europe and western Asia. Native sulfur may be produced by geological processes alone. Fossil-based sulfur deposits from salt domes were once
6946-573: Is mildly acidic: Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide (see below, under precautions ). The two principal sulfur oxides are obtained by burning sulfur: Many other sulfur oxides are observed including the sulfur-rich oxides include sulfur monoxide , disulfur monoxide , disulfur dioxides, and higher oxides containing peroxo groups. Sulfur reacts with fluorine to give
7097-413: Is not commercially available. Where a base is desired, the halides have been used in conjunction with sodium acetate . The use of platinum(II) acetylacetonate has also been reported. Several barium platinides have been synthesized in which platinum exhibits negative oxidation states ranging from −1 to −2. These include BaPt, Ba 3 Pt 2 , and Ba 2 Pt . Caesium platinide, Cs 2 Pt ,
7248-436: Is often used in characterizing the elements. Density is often expressed in grams per cubic centimetre (g/cm ). Since several elements are gases at commonly encountered temperatures, their densities are usually stated for their gaseous forms; when liquefied or solidified, the gaseous elements have densities similar to those of the other elements. When an element has allotropes with different densities, one representative allotrope
7399-523: Is one of the rarer elements in Earth's crust , with an average abundance of approximately 5 μg /kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa , which accounts for ~80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and
7550-470: Is probably the most important platinum compound, as it serves as the precursor for many other platinum compounds. By itself, it has various applications in photography, zinc etchings, indelible ink , plating, mirrors, porcelain coloring, and as a catalyst. Treatment of hexachloroplatinic acid with an ammonium salt, such as ammonium chloride , gives ammonium hexachloroplatinate , which is relatively insoluble in ammonium solutions. Heating this ammonium salt in
7701-399: Is produced by rapid cooling of molten sulfur—for example, by pouring it into cold water. X-ray crystallography studies show that the amorphous form may have a helical structure with eight atoms per turn. The long coiled polymeric molecules make the brownish substance elastic , and in bulk it has the feel of crude rubber. This form is metastable at room temperature and gradually reverts to
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#17327649443817852-557: Is the 10th most common element in the universe . Sulfur, usually as sulfide, is present in many types of meteorites . Ordinary chondrites contain on average 2.1% sulfur, and carbonaceous chondrites may contain as much as 6.6%. It is normally present as troilite (FeS), but there are exceptions, with carbonaceous chondrites containing free sulfur, sulfates and other sulfur compounds. The distinctive colors of Jupiter 's volcanic moon Io are attributed to various forms of molten, solid, and gaseous sulfur. In July 2024, elemental sulfur
8003-411: Is the first of a series of square planar platinum(II)-containing chemotherapy drugs. Others include carboplatin and oxaliplatin . These compounds are capable of crosslinking DNA , and kill cells by similar pathways to alkylating chemotherapeutic agents . (Side effects of cisplatin include nausea and vomiting, hair loss, tinnitus, hearing loss, and nephrotoxicity.) Organoplatinum compounds such as
8154-424: Is the least abundant at only 0.01%. Of the naturally occurring isotopes, only Pt is unstable, though it decays with a half-life of 6.5 × 10 years, causing an activity of 15 Bq /kg of natural platinum. Other isotopes can undergo alpha decay , but their decay has never been observed, therefore they are considered stable. Platinum also has 38 synthetic isotopes ranging in atomic mass from 165 to 208, making
8305-426: Is the mass number) is an atom with 24 nucleons (12 protons and 12 neutrons). Whereas the mass number simply counts the total number of neutrons and protons and is thus an integer, the atomic mass of a particular isotope (or "nuclide") of the element is the mass of a single atom of that isotope, and is typically expressed in daltons (symbol: Da), or universal atomic mass units (symbol: u). Its relative atomic mass
8456-448: Is the production of sulfuric acid for sulfate and phosphate fertilizers , and other chemical processes. Sulfur is used in matches , insecticides , and fungicides . Many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, bad breath , grapefruit , and garlic are due to organosulfur compounds. Hydrogen sulfide gives the characteristic odor to rotting eggs and other biological processes. Sulfur
8607-532: Is typically selected in summary presentations, while densities for each allotrope can be stated where more detail is provided. For example, the three familiar allotropes of carbon ( amorphous carbon , graphite , and diamond ) have densities of 1.8–2.1, 2.267, and 3.515 g/cm , respectively. The elements studied to date as solid samples have eight kinds of crystal structures : cubic , body-centered cubic , face-centered cubic, hexagonal , monoclinic , orthorhombic , rhombohedral , and tetragonal . For some of
8758-408: Is used as a reagent to make the polymer rayon and many organosulfur compounds. Unlike carbon monoxide , carbon monosulfide is stable only as an extremely dilute gas, found between solar systems. Organosulfur compounds are responsible for some of the unpleasant odors of decaying organic matter. They are widely known as the odorant in domestic natural gas, garlic odor, and skunk spray, as well as
8909-430: Is used as an alloying agent for various metal products, including fine wires, noncorrosive laboratory containers, medical instruments, dental prostheses, electrical contacts, and thermocouples. Platinum-cobalt, an alloy of roughly three parts platinum and one part cobalt, is used to make relatively strong permanent magnets . Platinum-based anodes are used in ships, pipelines, and steel piers. Platinum drugs are used to treat
9060-410: Is used in fuel cells as a catalyst for the reduction of oxygen . As a fuel cell catalyst, platinum enables hydrogen and oxygen reactions to take place at an optimum rate. It is used in platinum-based proton exchange membrane (PEM) technologies required in green hydrogen production as well as fuel cell electric vehicle adoption (FCEV) . From 1889 to 1960, the meter was defined as the length of
9211-434: Is used in the glass industry to manipulate molten glass, which does not " wet " platinum. As a heavy metal , it leads to health problems upon exposure to its salts ; but due to its corrosion resistance, metallic platinum has not been linked to adverse health effects. Compounds containing platinum, such as cisplatin , oxaliplatin and carboplatin , are applied in chemotherapy against certain types of cancer. Pure platinum
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#17327649443819362-417: Is used in two different but closely related meanings: it can mean a chemical substance consisting of a single kind of atoms, or it can mean that kind of atoms as a component of various chemical substances. For example, molecules of water (H 2 O) contain atoms of hydrogen (H) and oxygen (O), so water can be said as a compound consisting of the elements hydrogen (H) and oxygen (O) even though it does not contain
9513-429: Is very strong; fullerenes , which have nearly spherical shapes; and carbon nanotubes , which are tubes with a hexagonal structure (even these may differ from each other in electrical properties). The ability of an element to exist in one of many structural forms is known as 'allotropy'. The reference state of an element is defined by convention, usually as the thermodynamically most stable allotrope and physical state at
9664-590: Is widely used. For example, the French chemical terminology distinguishes élément chimique (kind of atoms) and corps simple (chemical substance consisting of a single kind of atoms); the Russian chemical terminology distinguishes химический элемент and простое вещество . Almost all baryonic matter in the universe is composed of elements (among rare exceptions are neutron stars ). When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds . Only
9815-761: The Pt ion has a great affinity for sulfide and sulfur ligands. Numerous DMSO complexes have been reported and care is taken in the choosing of reaction solvents. In 2007, the German scientist Gerhard Ertl won the Nobel Prize in Chemistry for determining the detailed molecular mechanisms of the catalytic oxidation of carbon monoxide over platinum ( catalytic converter ). Platinum has six naturally occurring isotopes : Pt , Pt , Pt , Pt , Pt , and Pt . The most abundant of these
9966-776: The Bushveld complex , Gauteng , South Africa . In 1865, chromites were identified in the Bushveld region of South Africa, followed by the discovery of platinum in 1906. In 1924, the geologist Hans Merensky discovered a large supply of platinum in the Bushveld Igneous Complex in South Africa. The specific layer he found, named the Merensky Reef , contains around 75% of the world's known platinum. The large copper–nickel deposits near Norilsk in Russia , and
10117-583: The Chocó Department , Colombia are still a source for platinum-group metals. Another large alluvial deposit is in the Ural Mountains , Russia, and it is still mined. In nickel and copper deposits, platinum-group metals occur as sulfides (e.g., (Pt,Pd)S) , tellurides (e.g., PtBiTe ), antimonides (PdSb), and arsenides (e.g. PtAs 2 ), and as end alloys with nickel or copper. Platinum arsenide, sperrylite ( PtAs 2 ),
10268-497: The Hershey-Chase experiment . Because of the weak beta activity of S, its compounds are relatively safe as long as they are not ingested or absorbed by the body. S is created inside massive stars, at a depth where the temperature exceeds 2.5×10 K, by the fusion of one nucleus of silicon plus one nucleus of helium. As this nuclear reaction is part of the alpha process that produces elements in abundance, sulfur
10419-583: The International Temperature Scale of 1990 (ITS-90), the international calibration standard for temperature measurements. The resistance wire in the thermometer is made of pure platinum (NIST manufactured the wires from platinum bar stock with a chemical purity of 99.999% by weight). In addition to laboratory uses, Platinum Resistance Thermometry (PRT) also has many industrial applications, industrial standards include ASTM E1137 and IEC 60751. The standard hydrogen electrode also uses
10570-489: The International Union of Pure and Applied Chemistry (IUPAC) had recognized a total of 118 elements. The first 94 occur naturally on Earth , and the remaining 24 are synthetic elements produced in nuclear reactions. Save for unstable radioactive elements (radioelements) which decay quickly, nearly all elements are available industrially in varying amounts. The discovery and synthesis of further new elements
10721-638: The Latin alphabet are likely to use the IUPAC element names. According to IUPAC, element names are not proper nouns; therefore, the full name of an element is not capitalized in English, even if derived from a proper noun , as in californium and einsteinium . Isotope names are also uncapitalized if written out, e.g., carbon-12 or uranium-235 . Chemical element symbols (such as Cf for californium and Es for einsteinium), are always capitalized (see below). In
10872-704: The New World . It was used extensively as such by American publications before the international standardization (in 1950). Before chemistry became a science , alchemists designed arcane symbols for both metals and common compounds. These were however used as abbreviations in diagrams or procedures; there was no concept of atoms combining to form molecules . With his advances in the atomic theory of matter, John Dalton devised his own simpler symbols, based on circles, to depict molecules. Sulfur Sulfur (also spelled sulphur in British English )
11023-680: The Sudbury Basin , Canada , are the two other large deposits. In the Sudbury Basin, the huge quantities of nickel ore processed make up for the fact platinum is present as only 0.5 ppm in the ore. Smaller reserves can be found in the United States, for example in the Absaroka Range in Montana . In 2010, South Africa was the top producer of platinum, with an almost 77% share, followed by Russia at 13%; world production in 2010
11174-513: The adulteration of gold with platinum impurities. In 1735, Antonio de Ulloa and Jorge Juan y Santacilia saw Native Americans mining platinum while the Spaniards were travelling through Colombia and Peru for eight years. Ulloa and Juan found mines with the whitish metal nuggets and took them home to Spain. Antonio de Ulloa returned to Spain and established the first mineralogy lab in Spain and
11325-423: The kinetic isotope effect is significant). Thus, all carbon isotopes have nearly identical chemical properties because they all have six electrons, even though they may have 6 to 8 neutrons. That is why atomic number, rather than mass number or atomic weight , is considered the identifying characteristic of an element. The symbol for atomic number is Z . Isotopes are atoms of the same element (that is, with
11476-408: The noble gases . Sulfur polycations, S 2+ 8 , S 2+ 4 and S 2+ 16 are produced when sulfur is reacted with oxidizing agents in a strongly acidic solution. The colored solutions produced by dissolving sulfur in oleum were first reported as early as 1804 by C. F. Bucholz, but the cause of the color and the structure of the polycations involved was only determined in
11627-405: The nuclear binding energy and electron binding energy. For example, the atomic mass of chlorine-35 to five significant digits is 34.969 Da and that of chlorine-37 is 36.966 Da. However, the relative atomic mass of each isotope is quite close to its mass number (always within 1%). The only isotope whose atomic mass is exactly a natural number is C, which has a mass of 12 Da; because
11778-473: The sulfate minerals , such as gypsum (calcium sulfate), alunite (potassium aluminium sulfate), and barite (barium sulfate). On Earth, just as upon Jupiter's moon Io, elemental sulfur occurs naturally in volcanic emissions, including emissions from hydrothermal vents . The main industrial source of sulfur has become petroleum and natural gas . Common oxidation states of sulfur range from −2 to +6. Sulfur forms stable compounds with all elements except
11929-409: The (among others) protein keratin , found in outer skin, hair, and feathers. Sulfur is one of the core chemical elements needed for biochemical functioning and is an elemental macronutrient for all living organisms. Sulfur forms several polyatomic molecules. The best-known allotrope is octasulfur , cyclo-S 8 . The point group of cyclo-S 8 is D 4d and its dipole moment is 0 D. Octasulfur
12080-484: The +10 oxidation state may be achievable. Zeise's salt , containing an ethylene ligand, was one of the first organometallic compounds discovered. Dichloro(cycloocta-1,5-diene)platinum(II) is a commercially available olefin complex, which contains easily displaceable cod ligands ("cod" being an abbreviation of 1,5-cyclooctadiene). The cod complex and the halides are convenient starting points to platinum chemistry. Cisplatin , or cis -diamminedichloroplatinum(II)
12231-414: The 2010s, it was thought that sulfate reduction could fractionate sulfur isotopes up to 46 permil and fractionation larger than 46 permil recorded in sediments must be due to disproportionation of sulfur compounds in the sediment. This view has changed since the 2010s as experiments showed that sulfate-reducing bacteria can fractionate to 66 permil. As substrates for disproportionation are limited by
12382-566: The 218 tonnes of platinum sold in 2014, 98 tonnes were used for vehicle emissions control devices (45%), 74.7 tonnes for jewelry (34%), 20.0 tonnes for chemical production and petroleum refining (9.2%), and 5.85 tonnes for electrical applications such as hard disk drives (2.7%). The remaining 28.9 tonnes went to various other minor applications, such as medicine and biomedicine, glassmaking equipment, investment, electrodes, anticancer drugs, oxygen sensors , spark plugs and turbine engines. The most common use of platinum
12533-535: The 3rd century, the Chinese had discovered that sulfur could be extracted from pyrite . Chinese Daoists were interested in sulfur's flammability and its reactivity with certain metals, yet its earliest practical uses were found in traditional Chinese medicine . The Wujing Zongyao of 1044 AD described various formulas for Chinese black powder , which is a mixture of potassium nitrate ( KNO 3 ), charcoal , and sulfur. Indian alchemists, practitioners of
12684-638: The 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope (except for technetium , element 43 and promethium , element 61, which have no stable isotopes). Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected. Some of these elements, notably bismuth (atomic number 83), thorium (atomic number 90), and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of
12835-487: The French, Italians, Greeks, Portuguese and Poles prefer "azote/azot/azoto" (from roots meaning "no life") for "nitrogen". For purposes of international communication and trade, the official names of the chemical elements both ancient and more recently recognized are decided by the International Union of Pure and Applied Chemistry (IUPAC), which has decided on a sort of international English language, drawing on traditional English names even when an element's chemical symbol
12986-412: The above antitumour agents, as well as soluble inorganic platinum complexes, are routinely characterised using Pt nuclear magnetic resonance spectroscopy . Archaeologists have discovered traces of platinum in the gold used in ancient Egyptian burials as early as 1200 BCE . For example, a small box from burial of Shepenupet II was found to be decorated with gold-platinum hieroglyphics. However,
13137-494: The activity of sulfate-reducing bacteria in the time of formation of the sample, or suggest the main sources of sulfur in ecosystems. However, there are ongoing discussions over the real reason for the δ S shifts, biological activity or postdeposit alteration. For example, when sulfide minerals are precipitated, isotopic equilibration among solids and liquid may cause small differences in the δ S values of co-genetic minerals. The differences between minerals can be used to estimate
13288-429: The alloy in hot aqua regia , precipitating the platinum with ammonium chloride , igniting the ammonium chloroplatinate, and hammering the resulting finely divided platinum to make it cohere. Franz Karl Achard made the first platinum crucible in 1784. He worked with the platinum by fusing it with arsenic, then later volatilizing the arsenic. Because the other platinum-family members were not discovered yet (platinum
13439-531: The area were bought secondhand through the antiquities trade rather than obtained by direct archeological excavation. To work the metal, they would combine gold and platinum powders by sintering . The resulting gold–platinum alloy would then be soft enough to shape with tools. The platinum used in such objects was not the pure element, but rather a naturally occurring mixture of the platinum group metals, with small amounts of palladium, rhodium, and iridium. The first European reference to platinum appears in 1557 in
13590-436: The atmospheric Ar . This fact may be used to verify the presence of recent (up to 1 year) atmospheric sediments in various materials. This isotope may be obtained artificially by different ways. In practice, the reaction Cl + n → S + p is used by irradiating potassium chloride with neutrons. The isotope S is used in various sulfur-containing compounds as a radioactive tracer for many biological studies, for example,
13741-487: The atomic masses of the elements (their atomic weights or atomic masses) do not always increase monotonically with their atomic numbers. The naming of various substances now known as elements precedes the atomic theory of matter, as names were given locally by various cultures to various minerals, metals, compounds, alloys, mixtures, and other materials, though at the time it was not known which chemicals were elements and which compounds. As they were identified as elements,
13892-600: The basis for commercial production in the United States, Russia, Turkmenistan, and Ukraine. Such sources have become of secondary commercial importance, and most are no longer worked but commercial production is still carried out in the Osiek mine in Poland. Common naturally occurring sulfur compounds include the sulfide minerals , such as pyrite (iron sulfide), cinnabar (mercury sulfide), galena (lead sulfide), sphalerite (zinc sulfide), and stibnite (antimony sulfide); and
14043-413: The chemical substances (di)hydrogen (H 2 ) and (di)oxygen (O 2 ), as H 2 O molecules are different from H 2 and O 2 molecules. For the meaning "chemical substance consisting of a single kind of atoms", the terms "elementary substance" and "simple substance" have been suggested, but they have not gained much acceptance in English chemical literature, whereas in some other languages their equivalent
14194-501: The composition of reaction products. While reaction between sulfur and oxygen under normal conditions gives sulfur dioxide (oxidation state +4), formation of sulfur trioxide (oxidation state +6) requires a temperature of 400–600 °C (750–1,100 °F) and presence of a catalyst. In reactions with elements of lesser electronegativity , it reacts as an oxidant and forms sulfides, where it has oxidation state −2. Sulfur reacts with nearly all other elements except noble gases, even with
14345-451: The crystalline molecular allotrope, which is no longer elastic. This process happens over a matter of hours to days, but can be rapidly catalyzed. Sulfur has 23 known isotopes , four of which are stable: S ( 94.99% ± 0.26% ), S ( 0.75% ± 0.02% ), S ( 4.25% ± 0.24% ), and S ( 0.01% ± 0.01% ). Other than S, with a half-life of 87 days, the radioactive isotopes of sulfur have half-lives less than 3 hours. The preponderance of S
14496-408: The dalton is defined as 1/12 of the mass of a free neutral carbon-12 atom in the ground state. The standard atomic weight (commonly called "atomic weight") of an element is the average of the atomic masses of all the chemical element's isotopes as found in a particular environment, weighted by isotopic abundance, relative to the atomic mass unit. This number may be a fraction that is not close to
14647-416: The discovery and use of elements began with early human societies that discovered native minerals like carbon , sulfur , copper and gold (though the modern concept of an element was not yet understood). Attempts to classify materials such as these resulted in the concepts of classical elements , alchemy , and similar theories throughout history. Much of the modern understanding of elements developed from
14798-406: The elements are available by name, atomic number, density, melting point, boiling point and chemical symbol , as well as ionization energy . The nuclides of stable and radioactive elements are also available as a list of nuclides , sorted by length of half-life for those that are unstable. One of the most convenient, and certainly the most traditional presentation of the elements, is in the form of
14949-470: The elements are often summarized using the periodic table, which powerfully and elegantly organizes the elements by increasing atomic number into rows ( "periods" ) in which the columns ( "groups" ) share recurring ("periodic") physical and chemical properties. The table contains 118 confirmed elements as of 2021. Although earlier precursors to this presentation exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869, who intended
15100-480: The elements can be uniquely sequenced by atomic number, conventionally from lowest to highest (as in a periodic table), sets of elements are sometimes specified by such notation as "through", "beyond", or "from ... through", as in "through iron", "beyond uranium", or "from lanthanum through lutetium". The terms "light" and "heavy" are sometimes also used informally to indicate relative atomic numbers (not densities), as in "lighter than carbon" or "heavier than lead", though
15251-413: The elements without any stable isotopes are technetium (atomic number 43), promethium (atomic number 61), and all observed elements with atomic number greater than 82. Of the 80 elements with at least one stable isotope, 26 have only one stable isotope. The mean number of stable isotopes for the 80 stable elements is 3.1 stable isotopes per element. The largest number of stable isotopes for a single element
15402-474: The elements, including consideration of their general physical and chemical properties, their states of matter under familiar conditions, their melting and boiling points, their densities, their crystal structures as solids, and their origins. Several terms are commonly used to characterize the general physical and chemical properties of the chemical elements. A first distinction is between metals , which readily conduct electricity , nonmetals , which do not, and
15553-416: The elements. Geoscientists also study the isotopes of metal sulfides in rocks and sediment to study environmental conditions in the Earth's past. Some of the main classes of sulfur-containing organic compounds include the following: Compounds with carbon–sulfur multiple bonds are uncommon, an exception being carbon disulfide , a volatile colorless liquid that is structurally similar to carbon dioxide. It
15704-492: The existing names for anciently known elements (e.g., gold, mercury, iron) were kept in most countries. National differences emerged over the element names either for convenience, linguistic niceties, or nationalism. For example, German speakers use "Wasserstoff" (water substance) for "hydrogen", "Sauerstoff" (acid substance) for "oxygen" and "Stickstoff" (smothering substance) for "nitrogen"; English and some other languages use "sodium" for "natrium", and "potassium" for "kalium"; and
15855-630: The explosive stellar nucleosynthesis that produced the heavy metals before the formation of our Solar System . At over 1.9 × 10 years, over a billion times longer than the estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any isotope, and is almost always considered on par with the 80 stable elements. The heaviest elements (those beyond plutonium, element 94) undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized . There are now 118 known elements. In this context, "known" means observed well enough, even from just
16006-630: The extent of early Egyptians' knowledge of the metal is unclear. It is quite possible they did not recognize there was platinum in their gold. The metal was used by Native Americans near modern-day Esmeraldas, Ecuador to produce artifacts of a white gold-platinum alloy. Archeologists usually associate the tradition of platinum-working in South America with the La Tolita Culture ( c. 600 BCE – 200 CE), but precise dates and location are difficult, as most platinum artifacts from
16157-529: The formation of Earth, they are certain to have completely decayed, and if present in novae, are in quantities too small to have been noted. Technetium was the first purportedly non-naturally occurring element synthesized, in 1937, though trace amounts of technetium have since been found in nature (and also the element may have been discovered naturally in 1925). This pattern of artificial production and later natural discovery has been repeated with several other radioactive naturally occurring rare elements. List of
16308-408: The gold, the platinum is precipitated as ammonium chloroplatinate by the addition of ammonium chloride . Ammonium chloroplatinate can be converted to platinum by heating. Unprecipitated hexachloroplatinate(IV) may be reduced with elemental zinc , and a similar method is suitable for small scale recovery of platinum from laboratory residues. Mining and refining platinum has environmental impacts. Of
16459-431: The half-lives predicted for the observationally stable lead isotopes range from 10 to 10 years. Elements with atomic numbers 43, 61, and 83 through 94 are unstable enough that their radioactive decay can be detected. Three of these elements, bismuth (element 83), thorium (90), and uranium (92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced
16610-399: The heaviest elements also undergo spontaneous fission . Isotopes that are not radioactive, are termed "stable" isotopes. All known stable isotopes occur naturally (see primordial nuclide ). The many radioisotopes that are not found in nature have been characterized after being artificially produced. Certain elements have no stable isotopes and are composed only of radioisotopes: specifically
16761-549: The heavy elements before the formation of the Solar System. For example, at over 1.9 × 10 years, over a billion times longer than the estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any isotope. The last 24 elements (those beyond plutonium, element 94) undergo radioactive decay with short half-lives and cannot be produced as daughters of longer-lived elements, and thus are not known to occur in nature at all. 1 The properties of
16912-406: The highly reactive sulfur tetrafluoride and the highly inert sulfur hexafluoride . Whereas fluorine gives S(IV) and S(VI) compounds, chlorine gives S(II) and S(I) derivatives. Thus, sulfur dichloride , disulfur dichloride , and higher chlorosulfanes arise from the chlorination of sulfur. Sulfuryl chloride and chlorosulfuric acid are derivatives of sulfuric acid; thionyl chloride (SOCl 2 )
17063-493: The largest documented single crystal measuring 22 cm × 16 cm × 11 cm (8.7 in × 6.3 in × 4.3 in). Historically, Sicily was a major source of sulfur in the Industrial Revolution . Lakes of molten sulfur up to about 200 m (660 ft) in diameter have been found on the sea floor, associated with submarine volcanoes , at depths where the boiling point of water
17214-415: The late 1960s. S 2+ 8 is deep blue, S 2+ 4 is yellow and S 2+ 16 is red. Reduction of sulfur gives various polysulfides with the formula S x , many of which have been obtained in crystalline form. Illustrative is the production of sodium tetrasulfide : Some of these dianions dissociate to give radical anions , such as S − 3 gives the blue color of
17365-446: The mixture in either of the two acids and recovering the remaining platinum. One suitable method for purification for the raw platinum, which contains platinum, gold, and the other platinum-group metals, is to process it with aqua regia , in which palladium, gold and platinum are dissolved, whereas osmium, iridium, ruthenium and rhodium stay unreacted. The gold is precipitated by the addition of iron(II) chloride and after filtering off
17516-573: The notoriously unreactive metal iridium (yielding iridium disulfide ). Some of those reactions require elevated temperatures. Sulfur forms over 30 solid allotropes , more than any other element. Besides S 8 , several other rings are known. Removing one atom from the crown gives S 7 , which is of a deeper yellow than S 8 . HPLC analysis of "elemental sulfur" reveals an equilibrium mixture of mainly S 8 , but with S 7 and small amounts of S 6 . Larger rings have been prepared, including S 12 and S 18 . Amorphous or "plastic" sulfur
17667-592: The ore, including gold, mercury, lead, copper, and iron. This led him to believe he was working with a single metal, but in truth the ore still contained the yet-undiscovered platinum-group metals. This led to inconsistent results in his experiments. At times, the platinum seemed malleable, but when it was alloyed with iridium, it would be much more brittle . Sometimes the metal was entirely incombustible, but when alloyed with osmium, it would volatilize. After several months, Chabaneau succeeded in producing 23 kilograms of pure, malleable platinum by hammering and compressing
17818-418: The periodic table, which groups together elements with similar chemical properties (and usually also similar electronic structures). The atomic number of an element is equal to the number of protons in each atom, and defines the element. For example, all carbon atoms contain 6 protons in their atomic nucleus ; so the atomic number of carbon is 6. Carbon atoms may have different numbers of neutrons; atoms of
17969-426: The periodic tables presented here includes: actinides , alkali metals , alkaline earth metals , halogens , lanthanides , transition metals , post-transition metals , metalloids , reactive nonmetals , and noble gases . In this system, the alkali metals, alkaline earth metals, and transition metals, as well as the lanthanides and the actinides, are special groups of the metals viewed in a broader sense. Similarly,
18120-536: The platinum alloy. Alloying this impure platinum residue called "plyoxen" with gold was the only solution at the time to obtain a pliable compound, but nowadays, very pure platinum is available and extremely long wires can be drawn from pure platinum, very easily, due to its crystalline structure, which is similar to that of many soft metals. In 1786, Charles III of Spain provided a library and laboratory to Pierre-François Chabaneau to aid in his research of platinum. Chabaneau succeeded in removing various impurities from
18271-467: The platinum-group metals as well as selenium and tellurium settle to the bottom of the cell as "anode mud", which forms the starting point for the extraction of the platinum-group metals. If pure platinum is found in placer deposits or other ores, it is isolated from them by various methods of subtracting impurities. Because platinum is significantly denser than many of its impurities, the lighter impurities can be removed by simply floating them away in
18422-520: The presence of hydrogen reduces it to elemental platinum. Potassium hexachloroplatinate is similarly insoluble, and hexachloroplatinic acid has been used in the determination of potassium ions by gravimetry . When hexachloroplatinic acid is heated, it decomposes through platinum(IV) chloride and platinum(II) chloride to elemental platinum, although the reactions do not occur stepwise: All three reactions are reversible. Platinum(II) and platinum(IV) bromides are known as well. Platinum hexafluoride
18573-411: The price of platinum tends to be as much as twice the price of gold, whereas during periods of economic uncertainty, the price of platinum tends to decrease due to reduced industrial demand, falling below the price of gold. Gold prices are more stable in slow economic times, as gold is considered a safe haven. Although gold is also used in industrial applications, especially in electronics due to its use as
18724-407: The product of sulfate reduction , the isotopic effect of disproportionation should be less than 16 permil in most sedimentary settings. In forest ecosystems, sulfate is derived mostly from the atmosphere; weathering of ore minerals and evaporites contribute some sulfur. Sulfur with a distinctive isotopic composition has been used to identify pollution sources, and enriched sulfur has been added as
18875-412: The pure element to exist in multiple chemical structures ( spatial arrangements of atoms ), known as allotropes , which differ in their properties. For example, carbon can be found as diamond , which has a tetrahedral structure around each carbon atom; graphite , which has layers of carbon atoms with a hexagonal structure stacked on top of each other; graphene , which is a single layer of graphite that
19026-420: The reaction products. The second, fourth and sixth ionization energies of sulfur are 2252 kJ/mol, 4556 kJ/mol and 8495.8 kJ/mol, respectively. The composition of reaction products of sulfur with oxidants (and its oxidation state) depends on whether releasing of reaction energy overcomes these thresholds. Applying catalysts and/or supply of external energy may vary sulfur's oxidation state and
19177-772: The reactive nonmetals and the noble gases are nonmetals viewed in the broader sense. In some presentations, the halogens are not distinguished, with astatine identified as a metalloid and the others identified as nonmetals. Another commonly used basic distinction among the elements is their state of matter (phase), whether solid , liquid , or gas , at standard temperature and pressure (STP). Most elements are solids at STP, while several are gases. Only bromine and mercury are liquid at 0 degrees Celsius (32 degrees Fahrenheit) and 1 atmosphere pressure; caesium and gallium are solid at that temperature, but melt at 28.4°C (83.2°F) and 29.8°C (85.6°F), respectively. Melting and boiling points , typically expressed in degrees Celsius at
19328-919: The remaining 11 elements have half lives too short for them to have been present at the beginning of the Solar System, and are therefore considered transient elements. Of these 11 transient elements, five ( polonium , radon , radium , actinium , and protactinium ) are relatively common decay products of thorium and uranium . The remaining six transient elements (technetium, promethium, astatine, francium , neptunium , and plutonium ) occur only rarely, as products of rare decay modes or nuclear reaction processes involving uranium or other heavy elements. Elements with atomic numbers 1 through 82, except 43 (technetium) and 61 (promethium), each have at least one isotope for which no radioactive decay has been observed. Observationally stable isotopes of some elements (such as tungsten and lead ), however, are predicted to be slightly radioactive with very long half-lives: for example,
19479-509: The rock lapis lazuli . This reaction highlights a distinctive property of sulfur: its ability to catenate (bind to itself by formation of chains). Protonation of these polysulfide anions produces the polysulfanes , H 2 S x , where x = 2, 3, and 4. Ultimately, reduction of sulfur produces sulfide salts: The interconversion of these species is exploited in the sodium–sulfur battery . Treatment of sulfur with hydrogen gives hydrogen sulfide . When dissolved in water, hydrogen sulfide
19630-624: The same element can have different numbers of neutrons in their nuclei, known as isotopes of the element. Two or more atoms can combine to form molecules . Some elements are formed from molecules of identical atoms , e. g. atoms of hydrogen (H) form diatomic molecules (H 2 ). Chemical compounds are substances made of atoms of different elements; they can have molecular or non-molecular structure. Mixtures are materials containing different chemical substances; that means (in case of molecular substances) that they contain different types of molecules. Atoms of one element can be transformed into atoms of
19781-495: The same element having different numbers of neutrons are known as isotopes of the element. The number of protons in the nucleus also determines its electric charge , which in turn determines the number of electrons of the atom in its non-ionized state. The electrons are placed into atomic orbitals that determine the atom's chemical properties . The number of neutrons in a nucleus usually has very little effect on an element's chemical properties; except for hydrogen (for which
19932-404: The same number of protons in their nucleus), but having different numbers of neutrons . Thus, for example, there are three main isotopes of carbon. All carbon atoms have 6 protons, but they can have either 6, 7, or 8 neutrons. Since the mass numbers of these are 12, 13 and 14 respectively, said three isotopes are known as carbon-12 , carbon-13 , and carbon-14 ( C, C, and C). Natural carbon
20083-457: The second half of the 20th century, physics laboratories became able to produce elements with half-lives too short for an appreciable amount of them to exist at any time. These are also named by IUPAC, which generally adopts the name chosen by the discoverer. This practice can lead to the controversial question of which research group actually discovered an element, a question that delayed the naming of elements with atomic number of 104 and higher for
20234-495: The sponge form while white-hot. Chabeneau realized the infusibility of platinum would lend value to objects made of it, and so started a business with Joaquín Cabezas producing platinum ingots and utensils. This started what is known as the "platinum age" in Spain. Platinum, along with the rest of the platinum-group metals , is obtained commercially as a by-product from nickel and copper mining and processing. During electrorefining of copper , noble metals such as silver, gold and
20385-496: The synthetically produced transuranic elements, available samples have been too small to determine crystal structures. Chemical elements may also be categorized by their origin on Earth, with the first 94 considered naturally occurring, while those with atomic numbers beyond 94 have only been produced artificially via human-made nuclear reactions. Of the 94 naturally occurring elements, 83 are considered primordial and either stable or weakly radioactive. The longest-lived isotopes of
20536-955: The table to illustrate recurring trends in the properties of the elements. The layout of the table has been refined and extended over time as new elements have been discovered and new theoretical models have been developed to explain chemical behavior. Use of the periodic table is now ubiquitous in chemistry, providing an extremely useful framework to classify, systematize and compare all the many different forms of chemical behavior. The table has also found wide application in physics , geology , biology , materials science , engineering , agriculture , medicine , nutrition , environmental health , and astronomy . Its principles are especially important in chemical engineering . The various chemical elements are formally identified by their unique atomic numbers, their accepted names, and their chemical symbols . The known elements have atomic numbers from 1 to 118, conventionally presented as Arabic numerals . Since
20687-465: The temperature of equilibration. The δ C and δ S of coexisting carbonate minerals and sulfides can be used to determine the pH and oxygen fugacity of the ore-bearing fluid during ore formation. Scientists measure the sulfur isotopes of minerals in rocks and sediments to study the redox conditions in past oceans. Sulfate-reducing bacteria in marine sediment fractionate sulfur isotopes as they take in sulfate and produce sulfide . Prior to
20838-516: The term " fire-and-brimstone " sermons , in which listeners are reminded of the fate of eternal damnation that await the unbelieving and unrepentant. It is from this part of the Bible that Hell is implied to "smell of sulfur" (likely due to its association with volcanic activity). According to the Ebers Papyrus , a sulfur ointment was used in ancient Egypt to treat granular eyelids. Sulfur
20989-478: The total number of known isotopes 44. The least stable of these are Pt and Pt , with half-lives of 260 μs, whereas the most stable is Pt with a half-life of 50 years. Most platinum isotopes decay by some combination of beta decay and alpha decay. Pt , Pt , and Pt decay primarily by electron capture . Pt and Pt are predicted to have energetically favorable double beta decay paths. Platinum
21140-621: The universe at large, in the spectra of stars and also supernovae, where short-lived radioactive elements are newly being made. The first 94 elements have been detected directly on Earth as primordial nuclides present from the formation of the Solar System , or as naturally occurring fission or transmutation products of uranium and thorium. The remaining 24 heavier elements, not found today either on Earth or in astronomical spectra, have been produced artificially: all are radioactive, with short half-lives; if any of these elements were present at
21291-528: The work of Dmitri Mendeleev , a Russian chemist who published the first recognizable periodic table in 1869. This table organizes the elements by increasing atomic number into rows (" periods ") in which the columns (" groups ") share recurring ("periodic") physical and chemical properties . The periodic table summarizes various properties of the elements, allowing chemists to derive relationships between them and to make predictions about elements not yet discovered, and potential new compounds. By November 2016,
21442-536: The writings of the Italian humanist Julius Caesar Scaliger as a description of an unknown noble metal found between Darién and Mexico, "which no fire nor any Spanish artifice has yet been able to liquefy". From their first encounters with platinum, the Spanish generally saw the metal as a kind of impurity in gold, and it was treated as such. It was often simply thrown away, and there was an official decree forbidding
21593-419: The β-S 8 molecules. Between its melting and boiling temperatures, octasulfur changes its allotrope again, turning from β-octasulfur to γ-sulfur, again accompanied by a lower density but increased viscosity due to the formation of polymers . At higher temperatures, the viscosity decreases as depolymerization occurs. Molten sulfur assumes a dark red color above 200 °C (392 °F). The density of sulfur
21744-511: Was 192,000 kg (423,000 lb). Large platinum deposits are present in the state of Tamil Nadu , India . Platinum exists in higher abundances on the Moon and in meteorites. Correspondingly, platinum is found in slightly higher abundances at sites of bolide impact on Earth that are associated with resulting post-impact volcanism, and can be mined economically; the Sudbury Basin is one such example. Hexachloroplatinic acid mentioned above
21895-631: Was accidentally discovered to exist on Mars after the Curiosity rover drove over and crushed a rock, revealing sulfur crystals inside it. Sulfur is the fifth most common element by mass in the Earth. Elemental sulfur can be found near hot springs and volcanic regions in many parts of the world, especially along the Pacific Ring of Fire ; such volcanic deposits are mined in Indonesia, Chile, and Japan. These deposits are polycrystalline, with
22046-552: Was determined by the Sun. Though it was assumed that the distribution of different sulfur isotopes would be more or less equal, it has been found that proportions of the two most abundant sulfur isotopes S and S varies in different samples. Assaying of the isotope ratio ( δ S ) in the samples suggests their chemical history, and with support of other methods, it allows to age-date the samples, estimate temperature of equilibrium between ore and water, determine pH and oxygen fugacity , identify
22197-400: Was known in ancient times, being mentioned for its uses in ancient India , ancient Greece , China , and ancient Egypt . Historically and in literature sulfur is also called brimstone , which means "burning stone". Almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum . The greatest commercial use of the element
22348-462: Was referenced in European writings as early as the 16th century, but it was not until Antonio de Ulloa published a report on a new metal of Colombian origin in 1748 that it began to be investigated by scientists. Platinum is used in catalytic converters , laboratory equipment, electrical contacts and electrodes , platinum resistance thermometers , dentistry equipment, and jewelry. Platinum
22499-512: Was the first in the list), Scheffer and Sickingen made the false assumption that due to its hardness—which is slightly more than for pure iron —platinum would be a relatively non-pliable material, even brittle at times, when in fact its ductility and malleability are close to that of gold. Their assumptions could not be avoided because the platinum they experimented with was highly contaminated with minute amounts of platinum-family elements such as osmium and iridium , amongst others, which embrittled
22650-501: Was the first to systematically study platinum, which was in 1748. His historical account of the expedition included a description of platinum as being neither separable nor calcinable . Ulloa also anticipated the discovery of platinum mines. After publishing the report in 1748, Ulloa did not continue to investigate the new metal. In 1758, he was sent to superintend mercury mining operations in Huancavelica . In 1741, Charles Wood ,
22801-640: Was used for fumigation in preclassical Greece ; this is mentioned in the Odyssey . Pliny the Elder discusses sulfur in book 35 of his Natural History , saying that its best-known source is the island of Melos . He mentions its use for fumigation, medicine, and bleaching cloth. A natural form of sulfur known as shiliuhuang ( 石硫黄 ) was known in China since the 6th century BC and found in Hanzhong . By
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