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88-562: OIB may refer to: Ocean island basalts , rocks Office for Infrastructure and logistics – Brussels Option Internationale du Baccalauréat of the French baccalauréat Orient-Institut Beirut , a research institute in Lebanon Personal identification number (Croatia) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

176-433: A density of 11.34 g/cm , which is greater than that of common metals such as iron (7.87 g/cm ), copper (8.93 g/cm ), and zinc (7.14 g/cm ). This density is the origin of the idiom to go over like a lead balloon . Some rarer metals are denser: tungsten and gold are both at 19.3 g/cm , and osmium —the densest metal known—has a density of 22.59 g/cm , almost twice that of lead. Lead

264-492: A few radioactive isotopes. One of them is lead-210; although it has a half-life of only 22.2 years, small quantities occur in nature because lead-210 is produced by a long decay series that starts with uranium-238 (that has been present for billions of years on Earth). Lead-211, −212, and −214 are present in the decay chains of uranium-235, thorium-232, and uranium-238, respectively, so traces of all three of these lead isotopes are found naturally. Minute traces of lead-209 arise from

352-605: A high U/ Pb ratio. Over time, as U decays to Pb, HIMU Earth materials develop particularly radiogenic (high) Pb/ Pb. If an Earth material has elevated U/ Pb (HIMU), then it will also have elevated U/ Pb, and therefore will produce radiogenic Pb compositions for both the Pb/ Pb and Pb/ Pb isotopic systems ( U decays Pb, U decays to Pb). Similarly, Earth materials with high U/Pb also tend to have high Th/Pb, and thus evolve to have high Pb/ Pb ( Th decays to Pb). Ocean island basalts with highly radiogenic Pb/ Pb, Pb/ Pb, Pb/ Pb are

440-602: A long half-life (i.e., longer than 704 million years) decays to a “radiogenic” daughter isotope. Changes in the parent/daughter ratio by, for example, mantle melting, result in changes in the radiogenic isotopic ratios. Thus, these radiogenic isotopic systems are sensitive to the timing, and degree, of parent/daughter the changed (or fractionated) parent daughter ratio, which then informs the process(es) responsible for generating observed radiogenic isotopic heterogeneity in ocean island basalts. In mantle geochemistry, any composition with relatively low Sr/ Sr, and high Nd/ Nd and Hf/ Hf,

528-558: A neutron and become thallium-204; this undergoes beta decay to give stable lead-204; on capturing another neutron, it becomes lead-205, which has a half-life of around 17 million years. Further captures result in lead-206, lead-207, and lead-208. On capturing another neutron, lead-208 becomes lead-209, which quickly decays into bismuth-209. On capturing another neutron, bismuth-209 becomes bismuth-210, and this beta decays to polonium-210, which alpha decays to lead-206. The cycle hence ends at lead-206, lead-207, lead-208, and bismuth-209. In

616-466: A polyhedral vertex and contributes two electrons to each covalent bond along an edge from their sp hybrid orbitals, the other two being an external lone pair . They may be made in liquid ammonia via the reduction of lead by sodium . Lead can form multiply-bonded chains , a property it shares with its lighter homologs in the carbon group. Its capacity to do so is much less because the Pb–Pb bond energy

704-437: A significant partial positive charge on lead. The result is a stronger contraction of the lead 6s orbital than is the case for the 6p orbital, making it rather inert in ionic compounds. The inert pair effect is less applicable to compounds in which lead forms covalent bonds with elements of similar electronegativity, such as carbon in organolead compounds. In these, the 6s and 6p orbitals remain similarly sized and sp hybridization

792-438: A single decay chain). In total, 43 lead isotopes have been synthesized, with mass numbers 178–220. Lead-205 is the most stable radioisotope, with a half-life of around 1.70 × 10  years. The second-most stable is lead-202, which has a half-life of about 52,500 years, longer than any of the natural trace radioisotopes. Bulk lead exposed to moist air forms a protective layer of varying composition. Lead(II) carbonate

880-452: A structure, with every alternate layer of oxygen atoms absent. Negative oxidation states can occur as Zintl phases , as either free lead anions, as in Ba 2 Pb, with lead formally being lead(−IV), or in oxygen-sensitive ring-shaped or polyhedral cluster ions such as the trigonal bipyramidal Pb 5 ion, where two lead atoms are lead(−I) and three are lead(0). In such anions, each atom is at

968-590: Is 6 times higher, copper 10 times, and mild steel 15 times higher); it can be strengthened by adding small amounts of copper or antimony . The melting point of lead—at 327.5 °C (621.5 °F) —is very low compared to most metals. Its boiling point of 1749 °C (3180 °F) is the lowest among the carbon-group elements. The electrical resistivity of lead at 20 °C is 192 nanoohm -meters, almost an order of magnitude higher than those of other industrial metals (copper at 15.43 nΩ·m ; gold 20.51 nΩ·m ; and aluminium at 24.15 nΩ·m ). Lead

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1056-520: Is a neurotoxin that accumulates in soft tissues and bones. It damages the nervous system and interferes with the function of biological enzymes , causing neurological disorders ranging from behavioral problems to brain damage, and also affects general health, cardiovascular, and renal systems. Lead's toxicity was first documented by ancient Greek and Roman writers, who noted some of the symptoms of lead poisoning , but became widely recognized in Europe in

1144-401: Is a superconductor at temperatures lower than 7.19  K ; this is the highest critical temperature of all type-I superconductors and the third highest of the elemental superconductors. Natural lead consists of four stable isotopes with mass numbers of 204, 206, 207, and 208, and traces of six short-lived radioisotopes with mass numbers 209–214 inclusive. The high number of isotopes

1232-420: Is a common constituent; the sulfate or chloride may also be present in urban or maritime settings. This layer makes bulk lead effectively chemically inert in the air. Finely powdered lead, as with many metals, is pyrophoric , and burns with a bluish-white flame. Fluorine reacts with lead at room temperature, forming lead(II) fluoride . The reaction with chlorine is similar but requires heating, as

1320-780: Is a mixed sulfide derived from galena; anglesite , PbSO 4 , is a product of galena oxidation; and cerussite or white lead ore, PbCO 3 , is a decomposition product of galena. Arsenic , tin , antimony , silver , gold , copper , bismuth are common impurities in lead minerals. World lead resources exceed two billion tons. Significant deposits are located in Australia, China, Ireland, Mexico, Peru, Portugal, Russia, United States. Global reserves—resources that are economically feasible to extract—totaled 88 million tons in 2016, of which Australia had 35 million, China 17 million, Russia 6.4 million. Typical background concentrations of lead do not exceed 0.1 μg/m in

1408-434: Is a referred to as “geochemically depleted”. High Sr/ Sr, and low Nd/ Nd and Hf/ Hf, is referred to as “geochemically enriched”. Relatively low isotopic ratios of Pb in mantle-derived rocks are described as unradiogenic ; relatively high ratios are described as radiogenic . These isotopic systems have provided evidence for a heterogenous lower mantle. There are several distinct “mantle domains” or endmembers that appear in

1496-426: Is a strong oxidizing agent, capable of oxidizing hydrochloric acid to chlorine gas. This is because the expected PbCl 4 that would be produced is unstable and spontaneously decomposes to PbCl 2 and Cl 2 . Analogously to lead monoxide , lead dioxide is capable of forming plumbate anions. Lead disulfide and lead diselenide are only stable at high pressures. Lead tetrafluoride , a yellow crystalline powder,

1584-404: Is a very soft metal with a Mohs hardness of 1.5; it can be scratched with a fingernail. It is quite malleable and somewhat ductile. The bulk modulus of lead—a measure of its ease of compressibility—is 45.8  GPa . In comparison, that of aluminium is 75.2 GPa; copper 137.8 GPa; and mild steel 160–169 GPa. Lead's tensile strength , at 12–17 MPa, is low (that of aluminium

1672-493: Is being constantly produced within the Earth via alpha decay (of U, Th, and Sm), but He is not being generated in appreciable quantities in the deep Earth, the ratio of He to He is decreasing in the interior of the Earth over time. The early Solar System began with high He/ He and therefore the Earth first accreted with high He/ He. Thus, in plume-derived lavas, high He/ He is an “ancient” geochemical signature that indicates

1760-445: Is common for the carbon group. The divalent state is rare for carbon and silicon , minor for germanium, important (but not prevailing) for tin, and is the more important of the two oxidation states for lead. This is attributable to relativistic effects , specifically the inert pair effect , which manifests itself when there is a large difference in electronegativity between lead and oxide , halide , or nitride anions, leading to

1848-408: Is consistent with lead's atomic number being even. Lead has a magic number of protons (82), for which the nuclear shell model accurately predicts an especially stable nucleus. Lead-208 has 126 neutrons, another magic number, which may explain why lead-208 is extraordinarily stable. With its high atomic number, lead is the heaviest element whose natural isotopes are regarded as stable; lead-208

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1936-414: Is exploited in the synthesis of other lead compounds. Few inorganic lead(IV) compounds are known. They are only formed in highly oxidizing solutions and do not normally exist under standard conditions. Lead(II) oxide gives a mixed oxide on further oxidation, Pb 3 O 4 . It is described as lead(II,IV) oxide , or structurally 2PbO·PbO 2 , and is the best-known mixed valence lead compound. Lead dioxide

2024-502: Is more prevalent than most other elements with atomic numbers greater than 40. Primordial lead—which comprises the isotopes lead-204, lead-206, lead-207, and lead-208—was mostly created as a result of repetitive neutron capture processes occurring in stars. The two main modes of capture are the s- and r-processes . In the s-process (s is for "slow"), captures are separated by years or decades, allowing less stable nuclei to undergo beta decay . A stable thallium-203 nucleus can capture

2112-650: Is not stable, as both the lead(III) ion and the larger complexes containing it are radicals . The same applies for lead(I), which can be found in such radical species. Numerous mixed lead(II,IV) oxides are known. When PbO 2 is heated in air, it becomes Pb 12 O 19 at 293 °C, Pb 12 O 17 at 351 °C, Pb 3 O 4 at 374 °C, and finally PbO at 605 °C. A further sesquioxide , Pb 2 O 3 , can be obtained at high pressure, along with several non-stoichiometric phases. Many of them show defective fluorite structures in which some oxygen atoms are replaced by vacancies: PbO can be considered as having such

2200-494: Is now possible to classify usefully and more conveniently on high field strength trace elements alone such as barium (Ba), caesium (Ce), rubidium (Rb), niobium (Nb) and terbium (Tb is chosen as proportion about constant in all IOB).  : The geochemistry of ocean island basalts is useful for studying the chemical and physical structure of Earth's mantle. Some mantle plumes that feed hotspot volcanism lavas are thought to originate as deep as

2288-499: Is older than 2.3 Ga, formed prior to the Great Oxidation Event and has resurfaced via mantle plume volcanism. Noble gas isotopic systems, such as He/ He, Ne/ Ne, and Xe/ Xe, have been used to demonstrate that parts of the lower mantle are relatively less degassed and have not been homogenized despite billions of years of mantle convective mixing. Some large, hot mantle plumes have anomalously high He/ He. Since He

2376-741: Is over three and a half times lower than that of the C–C bond . With itself, lead can build metal–metal bonds of an order up to three. With carbon, lead forms organolead compounds similar to, but generally less stable than, typical organic compounds (due to the Pb–C bond being rather weak). This makes the organometallic chemistry of lead far less wide-ranging than that of tin. Lead predominantly forms organolead(IV) compounds, even when starting with inorganic lead(II) reactants; very few organolead(II) compounds are known. The most well-characterized exceptions are Pb[CH(SiMe 3 ) 2 ] 2 and plumbocene . The lead analog of

2464-415: Is stable, but less so than the difluoride . Lead tetrachloride (a yellow oil) decomposes at room temperature, lead tetrabromide is less stable still, and the existence of lead tetraiodide is questionable. Some lead compounds exist in formal oxidation states other than +4 or +2. Lead(III) may be obtained, as an intermediate between lead(II) and lead(IV), in larger organolead complexes; this oxidation state

2552-413: Is still energetically favorable. Lead, like carbon, is predominantly tetravalent in such compounds. There is a relatively large difference in the electronegativity of lead(II) at 1.87 and lead(IV) at 2.33. This difference marks the reversal in the trend of increasing stability of the +4 oxidation state going down the carbon group; tin, by comparison, has values of 1.80 in the +2 oxidation state and 1.96 in

2640-448: Is the heaviest stable nucleus. (This distinction formerly fell to bismuth , with an atomic number of 83, until its only primordial isotope , bismuth-209, was found in 2003 to decay very slowly.) The four stable isotopes of lead could theoretically undergo alpha decay to isotopes of mercury with a release of energy, but this has not been observed for any of them; their predicted half-lives range from 10 to 10 years (at least 10 times

2728-538: Is the origin of the English word " plumbing ". Its ease of working, its low melting point enabling the easy fabrication of completely waterproof welded joints, and its resistance to corrosion ensured its widespread use in other applications, including pharmaceuticals, roofing, currency, warfare. Writers of the time, such as Cato the Elder , Columella , and Pliny the Elder , recommended lead (and lead-coated) vessels for

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2816-525: Is the so-called inert pair effect : the 6s electrons of lead become reluctant to participate in bonding, stabilising the +2 oxidation state and making the distance between nearest atoms in crystalline lead unusually long. Lead's lighter carbon group congeners form stable or metastable allotropes with the tetrahedrally coordinated and covalently bonded diamond cubic structure. The energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp orbitals. In lead,

2904-446: Is usefully exploited: lead tetraacetate is an important laboratory reagent for oxidation in organic synthesis. Tetraethyllead, once added to automotive gasoline, was produced in larger quantities than any other organometallic compound, and is still widely used in fuel for small aircraft . Other organolead compounds are less chemically stable. For many organic compounds, a lead analog does not exist. Lead's per-particle abundance in

2992-630: The Phoenicians worked deposits in the Iberian peninsula ; by 1600 BC, lead mining existed in Cyprus , Greece , and Sardinia . Rome's territorial expansion in Europe and across the Mediterranean, and its development of mining, led to it becoming the greatest producer of lead during the classical era , with an estimated annual output peaking at 80,000 tonnes. Like their predecessors,

3080-671: The Solar System is 0.121  ppb (parts per billion). This figure is two and a half times higher than that of platinum , eight times more than mercury , and seventeen times more than gold . The amount of lead in the universe is slowly increasing as most heavier atoms (all of which are unstable) gradually decay to lead. The abundance of lead in the Solar System since its formation 4.5 billion years ago has increased by about 0.75%. The solar system abundances table shows that lead, despite its relatively high atomic number,

3168-423: The core–mantle boundary (~2900 km deep). The composition of the ocean island basalts at hotspots provides a window into the composition of mantle domains in the plume conduit that melted to yield the basalts, thus providing clues as to how and when different reservoirs in the mantle formed. Early conceptual models for the geochemical structure of the mantle argued that the mantle was split into two reservoirs:

3256-804: The fall of Rome and did not reach comparable levels until the Industrial Revolution . Lead played a crucial role in the development of the printing press , as movable type could be relatively easily cast from lead alloys. In 2014, the annual global production of lead was about ten million tonnes, over half of which was from recycling. Lead's high density, low melting point, ductility and relative inertness to oxidation make it useful. These properties, combined with its relative abundance and low cost, resulted in its extensive use in construction , plumbing , batteries , bullets , shots , weights , solders , pewters , fusible alloys , lead paints , leaded gasoline , and radiation shielding . Lead

3344-401: The nucleus , and more shielded by smaller orbitals. The sum of the first four ionization energies of lead exceeds that of tin, contrary to what periodic trends would predict. This is explained by relativistic effects , which become significant in heavier atoms, which contract s and p orbitals such that lead's 6s electrons have larger binding energies than its 5s electrons. A consequence

3432-624: The +2 oxidation state rather than the +4 state common with lighter members of the carbon group . Exceptions are mostly limited to organolead compounds . Like the lighter members of the group, lead tends to bond with itself ; it can form chains and polyhedral structures. Since lead is easily extracted from its ores , prehistoric people in the Near East were aware of it . Galena is a principal ore of lead which often bears silver. Interest in silver helped initiate widespread extraction and use of lead in ancient Rome . Lead production declined after

3520-468: The +4 state. Lead(II) compounds are characteristic of the inorganic chemistry of lead. Even strong oxidizing agents like fluorine and chlorine react with lead to give only PbF 2 and PbCl 2 . Lead(II) ions are usually colorless in solution, and partially hydrolyze to form Pb(OH) and finally [Pb 4 (OH) 4 ] (in which the hydroxyl ions act as bridging ligands ), but are not reducing agents as tin(II) ions are. Techniques for identifying

3608-399: The Earth's building blocks) compositions. There are two geochemically enriched domains, named enriched mantle 1 (EM1), and enriched mantle 2 (EM2). Though broadly similar, there are some important distinctions between EM1 and EM2. EM1 has unradiogenic Pb/ Pb, moderately high Sr/ Sr, and extends to lower Nd/ Nd and Hf/ Hf than EM2. Pitcairn , Kerguelen - Heard , and Tristan - Gough are

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3696-626: The Egyptians had used lead for sinkers in fishing nets , glazes , glasses , enamels , ornaments . Various civilizations of the Fertile Crescent used lead as a writing material , as coins , and as a construction material . Lead was used by the ancient Chinese as a stimulant , as currency , as contraceptive , and in chopsticks . The Indus Valley civilization and the Mesoamericans used it for making amulets ; and

3784-475: The Romans obtained lead mostly as a by-product of silver smelting. Lead mining occurred in central Europe , Britain , Balkans , Greece , Anatolia , Hispania , the latter accounting for 40% of world production. Lead tablets were commonly used as a material for letters. Lead coffins, cast in flat sand forms and with interchangeable motifs to suit the faith of the deceased, were used in ancient Judea . Lead

3872-607: The atmosphere; 100 mg/kg in soil; 4 mg/kg in vegetation, 5 μg/L in fresh water and seawater. The modern English word lead is of Germanic origin; it comes from the Middle English leed and Old English lēad (with the macron above the "e" signifying that the vowel sound of that letter is long). The Old English word is derived from the hypothetical reconstructed Proto-Germanic * lauda- ('lead'). According to linguistic theory, this word bore descendants in multiple Germanic languages of exactly

3960-437: The course of the Earth's history, have remained in the crust instead of sinking deeper into the Earth's interior. This accounts for lead's relatively high crustal abundance of 14 ppm; it is the 36th most abundant element in the crust. The main lead-bearing mineral is galena (PbS), which is mostly found with zinc ores. Most other lead minerals are related to galena in some way; boulangerite , Pb 5 Sb 4 S 11 ,

4048-419: The current age of the universe). Three of the stable isotopes are found in three of the four major decay chains : lead-206, lead-207, and lead-208 are the final decay products of uranium-238 , uranium-235 , and thorium-232 , respectively. These decay chains are called the uranium chain , the actinium chain , and the thorium chain . Their isotopic concentrations in a natural rock sample depends greatly on

4136-428: The diiodide . Many lead(II) pseudohalides are known, such as the cyanide, cyanate, and thiocyanate . Lead(II) forms an extensive variety of halide coordination complexes , such as [PbCl 4 ] , [PbCl 6 ] , and the [Pb 2 Cl 9 ] n chain anion. Lead(II) sulfate is insoluble in water, like the sulfates of other heavy divalent cations . Lead(II) nitrate and lead(II) acetate are very soluble, and this

4224-434: The early Hadean . Lead Lead (pronounced "led") is a chemical element ; it has symbol Pb (from Latin plumbum ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable , and also has a relatively low melting point . When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has

4312-525: The eastern and southern Africans used lead in wire drawing . Because silver was extensively used as a decorative material and an exchange medium, lead deposits came to be worked in Asia Minor from 3000 BC; later, lead deposits were developed in the Aegean and Laurion . These three regions collectively dominated production of mined lead until c.  1200 BC . Beginning c. 2000 BC,

4400-578: The element its chemical symbol Pb . The word * ɸloud-io- is thought to be the origin of Proto-Germanic * bliwa- (which also means 'lead'), from which stemmed the German Blei . The name of the chemical element is not related to the verb of the same spelling, which is derived from Proto-Germanic * laidijan- ('to lead'). Metallic lead beads dating back to 7000–6500 BC have been found in Asia Minor and may represent

4488-428: The existence of a well-preserved helium reservoir in the deep mantle. The timing of the formation of this reservoir is constrained by observed anomalies of Xe/ Xe in ocean islands basalts, because Xe was only produced by decay of I during the first ~100 My of Earth's history. Together, high He/ He and Xe/ Xe indicate a relatively less degassed, primitive noble gas domain that has been relatively well preserved since

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4576-413: The first example of metal smelting . At that time, lead had few (if any) applications due to its softness and dull appearance. The major reason for the spread of lead production was its association with silver, which may be obtained by burning galena (a common lead mineral). The Ancient Egyptians were the first to use lead minerals in cosmetics, an application that spread to Ancient Greece and beyond;

4664-430: The group. Lead dihalides are well-characterized; this includes the diastatide and mixed halides, such as PbFCl. The relative insolubility of the latter forms a useful basis for the gravimetric determination of fluorine. The difluoride was the first solid ionically conducting compound to be discovered (in 1834, by Michael Faraday ). The other dihalides decompose on exposure to ultraviolet or visible light, especially

4752-410: The heavy radiogenic isotopic ratio of a melt, which upwells and becomes a volcanic rock on the surface of the Earth, reflects the isotopic ratio of the mantle source at the time of melting. The best studied heavy radiogenic isotope systems in ocean island basalts are Sr/ Sr, Nd/ Nd, Pb/ Pb, Pb/ Pb, Pb/ Pb, Hf/ Hf and, more recently, Os/ Os. In each of these systems, a radioactive parent isotope with

4840-409: The highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal . Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases , and it tends to form covalent bonds . Compounds of lead are usually found in

4928-449: The inert pair effect increases the separation between its s- and p-orbitals, and the gap cannot be overcome by the energy that would be released by extra bonds following hybridization. Rather than having a diamond cubic structure, lead forms metallic bonds in which only the p-electrons are delocalized and shared between the Pb ions. Lead consequently has a face-centered cubic structure like

5016-447: The late 19th century AD. A lead atom has 82 electrons , arranged in an electron configuration of [ Xe ]4f 5d 6s 6p . The sum of lead's first and second ionization energies —the total energy required to remove the two 6p electrons—is close to that of tin , lead's upper neighbor in the carbon group . This is unusual; ionization energies generally fall going down a group, as an element's outer electrons become more distant from

5104-560: The latter being stable only above around 488 °C. Litharge is the most commonly used inorganic compound of lead. There is no lead(II) hydroxide; increasing the pH of solutions of lead(II) salts leads to hydrolysis and condensation. Lead commonly reacts with heavier chalcogens. Lead sulfide is a semiconductor , a photoconductor , and an extremely sensitive infrared radiation detector . The other two chalcogenides, lead selenide and lead telluride , are likewise photoconducting. They are unusual in that their color becomes lighter going down

5192-441: The latter is not; this allows for lead–lead dating . As uranium decays into lead, their relative amounts change; this is the basis for uranium–lead dating . Lead-207 exhibits nuclear magnetic resonance , a property that has been used to study its compounds in solution and solid state, including in the human body. Apart from the stable isotopes, which make up almost all lead that exists naturally, there are trace quantities of

5280-464: The main component is ancient recycled basaltic oceanic crust which has inherited the trace element and isotopic signatures of a subduction zone dehydration process, with enrichment in high field strength elements. These mantle sources are inferred from differences in radiogenic isotope ratios that magmas inherit from their source rock. Sources have been defined from a combined analysis of strontium (Sr), neodymium (Nd) and lead (Pb) isotopes but it

5368-539: The neutrons are arranged in complete shells in the atomic nucleus, and it becomes harder to energetically accommodate more of them. When the neutron flux subsides, these nuclei beta decay into stable isotopes of osmium , iridium , platinum . Lead is classified as a chalcophile under the Goldschmidt classification , meaning it is generally found combined with sulfur. It rarely occurs in its native , metallic form. Many lead minerals are relatively light and, over

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5456-425: The ocean basins, ocean island basalts form seamounts , and in some cases, enough material is erupted that the rock protrudes from the ocean and forms an island, like at Hawaii , Samoa, and Iceland. Over time, however, thermal subsidence and mass loss via subaerial erosion causes islands to become completely submarine seamounts or guyots . Many ocean island basalts erupt at volcanic hotspots , which are thought to be

5544-435: The ocean island basalt record. When plotted in multi-isotope space, ocean island basalts tend to form arrays trending from a central composition out to an endmember with an extreme composition. The depleted mantle, or DM, is one endmember, and is defined by low Sr/ Sr, Pb/ Pb, Pb/ Pb, Pb/ Pb, and high Nd/ Nd and Hf/ Hf. The DM is therefore geochemically depleted, and relatively unradiogenic. Mid-ocean ridges passively sample

5632-418: The preparation of sweeteners and preservatives added to wine and food. The lead conferred an agreeable taste due to the formation of "sugar of lead" ( lead(II) acetate ), whereas copper vessels imparted a bitter flavor through verdigris formation. This metal was by far the most used material in classical antiquity, and it is appropriate to refer to the (Roman) Lead Age. Lead was to the Romans what plastic

5720-414: The presence of the Pb ion in water generally rely on the precipitation of lead(II) chloride using dilute hydrochloric acid. As the chloride salt is sparingly soluble in water, in very dilute solutions the precipitation of lead(II) sulfide is instead achieved by bubbling hydrogen sulfide through the solution. Lead monoxide exists in two polymorphs , litharge α-PbO (red) and massicot β-PbO (yellow),

5808-422: The presence of these three parent uranium and thorium isotopes. For example, the relative abundance of lead-208 can range from 52% in normal samples to 90% in thorium ores; for this reason, the standard atomic weight of lead is given to only one decimal place. As time passes, the ratio of lead-206 and lead-207 to lead-204 increases, since the former two are supplemented by radioactive decay of heavier elements while

5896-464: The product of mantle plumes. There are thousands of seamounts that are not clearly associated with upwelling mantle plumes, and there are chains of seamounts that are not age progressive. Seamounts that are not clearly linked to a mantle plume indicate that regional mantle composition and tectonic activity may also play important roles in producing intraplate volcanism. There are various sources identified for ocean island basalt magma in Earth's mantle but

5984-698: The products of HIMU mantle domains. St. Helena , and several islands in the Cook - Austral volcanic lineament (e.g., Mangaia ) are the type localities for HIMU ocean island basalts. The final mantle domain discussed here is the common composition that ocean island basalts trend toward in radiogenic isotopic multi-space. This is also most prevalent mantle source in ocean island basalts, and has intermediate to geochemically depleted Sr/ Sr, Nd/ Nd, and Hf/ Hf, as well as intermediate Pb/ Pb, Pb/ Pb, Pb/ Pb.  This central mantle domain has several names, each with slightly different implications. PREMA, or “Prevalent Mantle”

6072-432: The r-process (r is for "rapid"), captures happen faster than nuclei can decay. This occurs in environments with a high neutron density, such as a supernova or the merger of two neutron stars . The neutron flux involved may be on the order of 10 neutrons per square centimeter per second. The r-process does not form as much lead as the s-process. It tends to stop once neutron-rich nuclei reach 126 neutrons. At this point,

6160-541: The resulting chloride layer diminishes the reactivity of the elements. Molten lead reacts with the chalcogens to give lead(II) chalcogenides. Lead metal resists sulfuric and phosphoric acid but not hydrochloric or nitric acid ; the outcome depends on insolubility and subsequent passivation of the product salt. Organic acids, such as acetic acid , dissolve lead in the presence of oxygen. Concentrated alkalis dissolve lead and form plumbites . Lead shows two main oxidation states: +4 and +2. The tetravalent state

6248-518: The same meaning. There is no consensus on the origin of the Proto-Germanic * lauda- . One hypothesis suggests it is derived from Proto-Indo-European * lAudh- ('lead'; capitalization of the vowel is equivalent to the macron). Another hypothesis suggests it is borrowed from Proto-Celtic * ɸloud-io- ('lead'). This word is related to the Latin plumbum , which gave

6336-470: The same physical mantle source, as evidenced by their slightly distinct arrays in radiogenic isotopic multi-space. Thus, hotspots that are categorized as “EM1”, “EM2”, “HIMU”, or “FOZO”, may each sample physically distinct, but compositionally similar, portions of the mantle. Furthermore, some hotspot chains host lavas with wide range of isotopic compositions so that the plume source seems to either sample multiple domains which can be sampled at different times in

6424-546: The same physical reservoir in the deep mantle. Instead, mantle domains with similar radiogenic isotopic compositions sampled at different hotspot localities are thought to share similar geologic histories. For example, the EM2 hotspots of Samoa and Society are both thought to have a mantle source that contains recycled upper continental crust, an idea that is supported by stable isotope observations, including δ O and δ Li. The isotopic similarities do not imply that Samoa and Society have

6512-491: The similarly sized divalent metals calcium and strontium . Pure lead has a bright, shiny gray appearance with a hint of blue. It tarnishes on contact with moist air and takes on a dull appearance, the hue of which depends on the prevailing conditions. Characteristic properties of lead include high density , malleability, ductility, and high resistance to corrosion due to passivation . Lead's close-packed face-centered cubic structure and high atomic weight result in

6600-588: The simplest organic compound , methane , is plumbane . Plumbane may be obtained in a reaction between metallic lead and atomic hydrogen. Two simple derivatives, tetramethyllead and tetraethyllead , are the best-known organolead compounds. These compounds are relatively stable: tetraethyllead only starts to decompose if heated or if exposed to sunlight or ultraviolet light. With sodium metal, lead readily forms an equimolar alloy that reacts with alkyl halides to form organometallic compounds such as tetraethyllead. The oxidizing nature of many organolead compounds

6688-561: The surface expressions of melting of thermally buoyant, rising conduits of hot rock in the Earth's mantle , called mantle plumes . Some such hotspot volcanic chains are believed to have started with the formation of large igneous provinces . Mantle plume conduits may drift slowly, but Earth's tectonic plates drift more rapidly relative to mantle plumes. As a result, the relative motion of Earth's tectonic plates over mantle plumes produces age-progressive chains of volcanic islands and seamounts with

6776-477: The surface in buoyantly rising mantle plumes. Sulfur isotopic analyses have shown mass-independent-fractionation (MIF) in the sulfur isotopes in some plume-derived lavas. MIF of sulfur isotopes is a phenomenon that occurred in Earth's atmosphere only before the Great Oxidation Event ~2.3 Ga. The presence of recycled material with MIF signatures indicates that some of the recycled material brought

6864-446: The title OIB . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=OIB&oldid=882538678 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Ocean island basalt In

6952-556: The type localities of EM1.  EM2 is defined by higher Sr/ Sr than EM1, and higher Nd/ Nd and Hf/ Hf at a given Sr/ Sr value, and intermediate Pb/ Pb. Samoa and Society are the archetypal EM2 localities. Another distinct mantle domain is the HIMU mantle. In isotope geochemistry, the Greek letter μ (or mu) is used to describe the U/ Pb, such that ‘high μ’ (abbreviated HIMU) describes

7040-532: The upper mantle and MORBs are typically geochemically depleted, and therefore it is widely accepted that the upper mantle is composed mostly of depleted mantle. Thus, the term depleted MORB mantle (DMM) is often used to describe the upper mantle that sources mid-ocean ridge volcanism. Ocean island basalts also sample geochemically depleted mantle domains. In fact, most ocean island basalts are geochemically depleted, and <10% of ocean island basalts have lavas that extend to geochemically enriched (i.e., Nd/ Nd lower than

7128-497: The upper mantle and entering the lower mantle, which indicates that the lower mantle cannot be isolated. Additionally, the isotopic heterogeneity observed in plume-derived ocean island basalts argues against a homogenous lower mantle. Heavy, radiogenic isotopes are a particularly useful tool for studying the composition of mantle sources because isotopic ratios are not sensitive to mantle melting. According tradition subclassification used Sr-Nd-Pb-Hf-He isotopic ratios. This means that

7216-508: The upper mantle and the lower mantle. The upper mantle was thought to be geochemically depleted due to melt extraction which formed Earth's continents. The lower mantle was thought to be homogenous and “ primitive ”. (Primitive, in this case, refers to silicate material that represents the building blocks of the planet that has not been modified by melt extraction, or mixed with subducted materials, since Earth's accretion and core formation.) Seismic tomography showed subducted slabs passing through

7304-403: The very rare cluster decay of radium-223, one of the daughter products of natural uranium-235, and the decay chain of neptunium-237, traces of which are produced by neutron capture in uranium ores. Lead-213 also occurs in the decay chain of neptunium-237. Lead-210 is particularly useful for helping to identify the ages of samples by measuring its ratio to lead-206 (both isotopes are present in

7392-405: The volcanic evolution of a hotspot. Isotopic systems help to deconvolve the geologic processes that contributed to, and in some cases the timing of, the formation of these mantle domains. Some important examples include the presence of crustal fingerprints in enriched mantle sources that indicate that material from Earth's continents and oceans can be subducted into the mantle and brought back up to

7480-469: The youngest, active volcanoes located above the axis of the mantle plume while older, inactive volcanoes are located progressively farther away from the plume conduit ( see Figure 1 ). Hotspot chains can record tens of millions of years of continuous volcanic history; for example, the oldest seamounts in the Hawaiian–Emperor seamount chain are over 80 million years old. Not all ocean island basalts are

7568-425: The “Primitive Helium Mantle”, or PHEM. Finally, Hanan and Graham (1996) used the term “C” (for common component) to describe a common mixing component in mantle derived rocks. The presence of a particular mantle domain in ocean island basalts from two hotspots, signaled by a particular radiogenic isotopic composition, does not necessarily indicate that mantle plumes with similar isotopic compositions are sourced from

7656-414: Was the first term coined by Zindler and Hart (1986) to describe the most common composition sampled by ocean island basalts. Hart et al. (1992) later named the location of the intersection of ocean island basalt compositions in radiogenic isotopic multi-space as the “Focus Zone”, or FOZO. Farley et al. (1992) in the same year described a high He/ He (a primitive geochemical signature) component in plumes as

7744-534: Was used to make sling bullets from the 5th century BC. In Roman times, lead sling bullets were amply used, and were effective at a distance of between 100 and 150 meters. The Balearic slingers , used as mercenaries in Carthaginian and Roman armies, were famous for their shooting distance and accuracy. Lead was used for making water pipes in the Roman Empire ; the Latin word for the metal, plumbum ,

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