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89-432: The paper clip's widespread use in various settings, from offices to educational institutions, underscores its functional design and adaptability. While primarily designed for binding papers, its versatility has led to a range of applications, both practical and creative. Paper clips usually have an oblong shape with straight sides, but may also be triangular or circular, or have more elaborate shapes. The most common material

178-578: A plasma (physics) is a metallic conductor and the charged particles in a plasma have many properties in common with those of electrons in elemental metals, particularly for white dwarf stars. Metals are relatively good conductors of heat , which in metals is transported mainly by the conduction electrons. At higher temperatures the electrons can occupy slightly higher energy levels given by Fermi–Dirac statistics . These have slightly higher momenta ( kinetic energy ) and can pass on thermal energy. The empirical Wiedemann–Franz law states that in many metals

267-435: A semiconducting metalloid such as boron has an electrical conductivity 1.5 × 10 S/cm. With one exception, metallic elements reduce their electrical conductivity when heated. Plutonium increases its electrical conductivity when heated in the temperature range of around −175 to +125 °C, with anomalously large thermal expansion coefficient and a phase change from monoclinic to face-centered cubic near 100  °C. There

356-454: A base metal as it is oxidized relatively easily, although it does not react with HCl. The term noble metal (also for elements) is commonly used in opposition to base metal . Noble metals are less reactive, resistant to corrosion or oxidation , unlike most base metals . They tend to be precious metals, often due to perceived rarity. Examples include gold, platinum, silver, rhodium , iridium, and palladium. In alchemy and numismatics ,

445-443: A few—beryllium, chromium, manganese, gallium, and bismuth—are brittle. Arsenic and antimony, if admitted as metals, are brittle. Low values of the ratio of bulk elastic modulus to shear modulus ( Pugh's criterion ) are indicative of intrinsic brittleness. A material is brittle if it is hard for dislocations to move, which is often associated with large Burgers vectors and only a limited number of slip planes. A refractory metal

534-490: A keel, perpendicular to the sheet of paper. The impracticality of Vaaler's design may easily be demonstrated by cutting off the last outer loop and one long side from a regular Gem clip. The originator of the Norwegian paper clip myth was an engineer of the Norwegian national patent agency who visited Germany in the 1920s to register Norwegian patents in that country. He came across Vaaler's patent but failed to detect that it

623-489: A lapel or front pocket could be seen as "deux gaules" (two posts or poles) and be interpreted as a reference to the leader of the French Resistance , General Charles de Gaulle . The post-war years saw a widespread consolidation of the paper clip as a national symbol. Authors of books and articles on the history of Norwegian technology eagerly seized it to make a thin story more substantial. They chose to overlook

712-511: A lower atomic number) by neutron capture , with the two main modes of this repetitive capture being the s-process and the r-process . In the s-process ("s" stands for "slow"), singular captures are separated by years or decades, allowing the less stable nuclei to beta decay , while in the r-process ("rapid"), captures happen faster than nuclei can decay. Therefore, the s-process takes a more-or-less clear path: for example, stable cadmium-110 nuclei are successively bombarded by free neutrons inside

801-521: A modern cotter pin than a modern paper clip. Norwegian Johan Vaaler (1866–1910) has been identified as the inventor of the paper clip. He was granted patents in Germany and in the United States (1901) for a paper clip of similar design, but less functional and practical. Because it was more complicated to insert into the paper, Vaaler probably did not know that a better product was already on

890-457: A national symbol. During the German occupation of Norway during World War II, after pins or badges bearing national symbols or the initials of exiled King Haakon VII were banned, Norwegians began to wear paper clips in their lapels as a symbol of resistance to the occupiers and local Nazi authorities. The clips were meant to denote solidarity and unity ("we are bound together"). Their symbolism

979-422: A paper clip as the key to the bezel. A paper clip bent into a "U" can be used to start an ATX PSU without connecting it to a motherboard , by connecting the green to a black on the motherboard header. One or more paper clips can make a loopback device for a RS-232 interface (or indeed many interfaces). A paper clip could be installed in a Commodore 1541 disk drive as a flexible head-stop. The steel wire from

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1068-433: A paperclip can be used in dentistry to form a dental post . Another common use of paper clips is pipe smokers, including Cannabis smokers use straightened out paper clips to unclog their pipe or bong bowl . Another creative use of paper clips is in "paperclip art", where enthusiasts bend and twist paper clips into intricate designs and figures, ranging from simple shapes to detailed sculptures. This form of art showcases

1157-494: A patent examiner and manager at the patent office of Alfred Jørgen Bryn ( Alfred J. Bryns Patentkontor ) in Kristiania (now Oslo). In 1901, Vaaler designed a kind of binding to hold paper together, consisting of a thread of steel wire. He applied for a German patent on November 12 of that year and it was granted on June 6, 1901. He also filed an application for a United States patent on January 9, 1901. The U.S. patent

1246-499: A position he held until his death. As the employee of a patent office, he could easily have obtained a patent in Norway. His reasons for applying abroad are not known; it is possible that he wanted to secure the commercial rights internationally. Also, he may have been aware that a Norwegian manufacturer would find it difficult to introduce a new invention abroad, starting from the small home market. Vaaler's patents expired quietly, while

1335-514: A real metal. In this respect they resemble degenerate semiconductors . This explains why the electrical properties of semimetals are partway between those of metals and semiconductors . There are additional types, in particular Weyl and Dirac semimetals . The classic elemental semimetallic elements are arsenic , antimony , bismuth , α- tin (gray tin) and graphite . There are also chemical compounds , such as mercury telluride (HgTe), and some conductive polymers . Metallic elements up to

1424-511: A recessed button which the user might only rarely need. This is seen on most CD-ROM drives as an "emergency eject" should the power fail; also on early floppy disk drives (including the early Macintosh ). Various smartphones require the use of a long, thin object such as a paper clip to eject the SIM card and some Palm PDAs advise the use of a paper clip to reset the device. The trackball can be removed from early Logitech pointing devices using

1513-407: A result of a neutron star merger, thereby increasing the abundance of elements heavier than helium in the interstellar medium . When gravitational attraction causes this matter to coalesce and collapse new stars and planets are formed . The Earth's crust is made of approximately 25% of metallic elements by weight, of which 80% are light metals such as sodium, magnesium, and aluminium. Despite

1602-483: A role as investments and a store of value . Palladium and platinum, as of summer 2024, were valued at slightly less than half the price of gold, while silver is substantially less expensive. In electrochemistry, a valve metal is a metal which passes current in only one direction due to the formation of any insulating oxide later. There are many ceramic compounds which have metallic electrical conduction, but are not simple combinations of metallic elements. (They are not

1691-400: A star until they form cadmium-115 nuclei which are unstable and decay to form indium-115 (which is nearly stable, with a half-life 30 000 times the age of the universe). These nuclei capture neutrons and form indium-116, which is unstable, and decays to form tin-116, and so on. In contrast, there is no such path in the r-process. The s-process stops at bismuth due to the short half-lives of

1780-458: A symbol of resistance to the German occupiers and local Nazi authorities when other signs of resistance, such as flag pins or pins showing the cipher of the exiled King Haakon VII of Norway , were forbidden. Those wearing them did not yet see them as national symbols, as the myth of their Norwegian origin was not commonly known at the time. The clips were meant to denote solidarity and unity ("we are bound together"). The wearing of paper clips

1869-403: Is a metal that is very resistant to heat and wear. Which metals belong to this category varies; the most common definition includes niobium, molybdenum, tantalum, tungsten, and rhenium as well as their alloys. They all have melting points above 2000 °C, and a high hardness at room temperature. Several compounds such as titanium nitride are also described as refractory metals. A white metal

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1958-611: Is any of a range of white-colored alloys with relatively low melting points used mainly for decorative purposes. In Britain, the fine art trade uses the term "white metal" in auction catalogues to describe foreign silver items which do not carry British Assay Office marks, but which are nonetheless understood to be silver and are priced accordingly. A heavy metal is any relatively dense metal, either single element or multielement. Magnesium , aluminium and titanium alloys are light metals of significant commercial importance. Their densities of 1.7, 2.7 and 4.5 g/cm range from 19 to 56% of

2047-484: Is composed mostly of iron, is thought to be the source of Earth's protective magnetic field. The core lies above Earth's solid inner core and below its mantle. If it could be rearranged into a column having a 5 m (54 sq ft) footprint it would have a height of nearly 700 light years. The magnetic field shields the Earth from the charged particles of the solar wind, and cosmic rays that would otherwise strip away

2136-611: Is due to the freely moving electrons which reflect light. Although most elemental metals have higher densities than nonmetals , there is a wide variation in their densities, lithium being the least dense (0.534 g/cm ) and osmium (22.59 g/cm ) the most dense. Some of the 6d transition metals are expected to be denser than osmium, but their known isotopes are too unstable for bulk production to be possible Magnesium, aluminium and titanium are light metals of significant commercial importance. Their respective densities of 1.7, 2.7, and 4.5 g/cm can be compared to those of

2225-624: Is evidence that this and comparable behavior in transuranic elements is due to more complex relativistic and spin interactions which are not captured in simple models. All of the metallic alloys as well as conducting ceramics and polymers are metals by the same definition; for instance titanium nitride has delocalized states at the Fermi level. They have electrical conductivities similar to those of elemental metals. Liquid forms are also metallic conductors or electricity, for instance mercury . In normal conditions no gases are metallic conductors. However,

2314-478: Is in an 1893 advertisement for the "Gem Paper Clip". In 1904 Cushman & Denison registered a trademark for the "Gem" name in connection with paper clips. The announcement stated that it had been used since March 1, 1892, which may have been the time of its introduction in the United States. Paper clips are still sometimes called "Gem clips", and in Swedish the word for any paper clip is "gem". Definite proof that

2403-673: Is its appropriation as logo of the Year of Design ( L'any del disseny ) in Barcelona 2003, depicted on posters, T-shirts and other merchandise. It has been claimed that the paper clip was invented by English intellectual Herbert Spencer (1820–1903). Spencer registered a "binding-pin" on 2 September 1846, which was made and sold by Adolphus Ackermann for over a year, advertised as "for holding loose manuscripts, sermons, weekly papers, and all unstitched publications". Spencer's design, approximately 15 cm (5.9 in) unfolded, looked more like

2492-548: Is no external voltage . When a voltage is applied some move a little faster in a given direction, some a little slower so there is a net drift velocity which leads to an electric current. This involves small changes in which wavefunctions the electrons are in, changing to those with the higher momenta. Quantum mechanics dictates that one can only have one electron in a given state, the Pauli exclusion principle . Therefore there have to be empty delocalized electron states (with

2581-474: Is not. In the context of metals, an alloy is a substance having metallic properties which is composed of two or more elements . Often at least one of these is a metallic element; the term "alloy" is sometimes used more generally as in silicon–germanium alloys. An alloy may have a variable or fixed composition. For example, gold and silver form an alloy in which the proportions of gold or silver can be varied; titanium and silicon form an alloy TiSi 2 in which

2670-575: Is positioned at the center of a cube of eight others. In fcc and hcp, each atom is surrounded by twelve others, but the stacking of the layers differs. Some metals adopt different structures depending on the temperature. Many other metals with different elements have more complicated structures, such as rock-salt structure in titanium nitride or perovskite (structure) in some nickelates. The electronic structure of metals means they are relatively good conductors of electricity . The electrons all have different momenta , which average to zero when there

2759-507: Is steel or some other metal , but molded plastic is also used. Some other kinds of paper clips use a two-piece clamping system. Recent innovations include multi-colored plastic-coated paper clips and spring -fastened binder clips . Regular metal paper clips weigh about a gram. According to the Early Office Museum, the first patent for a bent wire paper clip was awarded in the United States to Samuel B. Fay in 1867. This clip

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2848-425: Is the proportion of its matter made up of the heavier chemical elements. The strength and resilience of some metals has led to their frequent use in, for example, high-rise building and bridge construction , as well as most vehicles, many home appliances , tools, pipes, and railroad tracks. Precious metals were historically used as coinage , but in the modern era, coinage metals have extended to at least 23 of

2937-423: Is to unfold the clip in a line and then twist the end in a right angle, trying to imitate a key and using it to lift the lock fixator. The second approach, which is more feasible but needs some practice, is to use the semi-unfolded clip kink for lifting when the clip is inserted through the hole where the handcuffs are closed. A paper clip image is the standard image for an attachment in an email client . In 1994,

3026-474: The Burgers vector of the dislocations are fairly small, which also means that the energy needed to produce one is small. In contrast, in an ionic compound like table salt the Burgers vectors are much larger and the energy to move a dislocation is far higher. Reversible elastic deformation in metals can be described well by Hooke's Law for the restoring forces, where the stress is linearly proportional to

3115-488: The Fermi level , as against nonmetallic materials which do not. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets). A metal may be a chemical element such as iron ; an alloy such as stainless steel ; or a molecular compound such as polymeric sulfur nitride . The general science of metals is called metallurgy , a subtopic of materials science ; aspects of

3204-415: The periodic table . If there are several, the most stable allotrope is considered. The situation changes with pressure: at extremely high pressures, all elements (and indeed all substances) are expected to metallize. Arsenic (As) has both a stable metallic allotrope and a metastable semiconducting allotrope at standard conditions. A similar situation affects carbon (C): graphite is metallic, but diamond

3293-539: The strain . A temperature change may lead to the movement of structural defects in the metal such as grain boundaries , point vacancies , line and screw dislocations , stacking faults and twins in both crystalline and non-crystalline metals. Internal slip , creep , and metal fatigue may also ensue. The atoms of simple metallic substances are often in one of three common crystal structures , namely body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal close-packed (hcp). In bcc, each atom

3382-486: The vicinity of iron (in the periodic table) are largely made via stellar nucleosynthesis . In this process, lighter elements from hydrogen to silicon undergo successive fusion reactions inside stars, releasing light and heat and forming heavier elements with higher atomic numbers. Heavier elements are not usually formed this way since fusion reactions involving such nuclei would consume rather than release energy. Rather, they are largely synthesised (from elements with

3471-400: The "Gem" conquered the world, including his own country. The Norwegian fish hook manufacturer O. Mustad & Son AS of Gjøvik has produced "Gem"-type paper clips since 1928. Vaaler's alleged invention of the paper clip became known in Norway after World War II and found its way into some encyclopedias. Events of that war contributed greatly to the mythical status of the paper clip as

3560-433: The "Gem" was used worldwide, including his own country. The failure of his design was its impracticality. Without the two full loops of the fully developed paper clip, it was difficult to insert sheets of paper into his clip. One could manipulate the end of the inner wire so that it could receive the sheet, but the outer wire was a dead end because it could not exploit the torsion principle. The clip would instead stand out like

3649-521: The American expert on technological innovations, Professor Henry J. Petroski . He refers to an 1883 article about "Gem Paper-Fasteners", praising them for being "better than ordinary pins" for "binding together papers on the same subject, a bundle of letters, or pages of a manuscript". Since the 1883 article had no illustration of this early "Gem", it may have been different from modern paper clips of that name. The earliest illustration of its current form

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3738-439: The Fermi energy. Many elements and compounds become metallic under high pressures, for example, iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure . Sodium becomes a nonmetal at pressure of just under two million times atmospheric pressure, and at even higher pressures it is expected to become a metal again. When discussing the periodic table and some chemical properties

3827-415: The United States imposed anti-dumping tariffs against China on paper clips. Patents Metal A metal (from Ancient Greek μέταλλον ( métallon )  'mine, quarry, metal') is a material that, when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. These properties are all associated with having electrons available at

3916-541: The United States since 1867, but the "Gem" type was not then (and has never been) patented. As an employee of Bryns patent office in Kristiania, Vaaler was familiar with patent legislation and procedures in Norway. His reasons for applying abroad are unknown, but it is possible that he had an exaggerated confidence in his invention and saw the need to secure the commercial rights internationally. Also, he may have been aware that Norwegian inventors would meet difficulties on

4005-483: The addition of chromium , nickel , and molybdenum to carbon steels (more than 10%) results in stainless steels with enhanced corrosion resistance. Other significant metallic alloys are those of aluminum , titanium , copper , and magnesium . Copper alloys have been known since prehistory— bronze gave the Bronze Age its name—and have many applications today, most importantly in electrical wiring. The alloys of

4094-599: The air to form oxides over various timescales ( potassium burns in seconds while iron rusts over years) which depend upon whether the native oxide forms a passivation layer that acts as a diffusion barrier . Some others, like palladium , platinum , and gold , do not react with the atmosphere at all; gold can form compounds where it gains an electron (aurides, e.g. caesium auride ). The oxides of elemental metals are often basic . However, oxides with very high oxidation states such as CrO 3 , Mn 2 O 7 , and OsO 4 often have strictly acidic reactions; and oxides of

4183-445: The chemical elements. There is also extensive use of multi-element metals such as titanium nitride or degenerate semiconductors in the semiconductor industry. The history of refined metals is thought to begin with the use of copper about 11,000 years ago. Gold, silver, iron (as meteoric iron), lead, and brass were likewise in use before the first known appearance of bronze in the fifth millennium BCE. Subsequent developments include

4272-406: The densities of other structural metals, such as iron (7.9) and copper (8.9) and their alloys. The term base metal refers to a metal that is easily oxidized or corroded , such as reacting easily with dilute hydrochloric acid (HCl) to form a metal chloride and hydrogen . The term is normally used for the elements, and examples include iron, nickel , lead , and zinc. Copper is considered

4361-495: The detailed structure of the metal's ion lattice. Taking into account the positive potential caused by the arrangement of the ion cores enables consideration of the electronic band structure and binding energy of a metal. Various models are applicable, the simplest being the nearly free electron model . Modern methods such as density functional theory are typically used. The elements which form metals usually form cations through electron loss. Most will react with oxygen in

4450-429: The electronic and thermal properties are also within the scope of condensed matter physics and solid-state chemistry , it is a multidisciplinary topic. In colloquial use materials such as steel alloys are referred to as metals, while others such as polymers, wood or ceramics are nonmetallic materials . A metal conducts electricity at a temperature of absolute zero , which is a consequence of delocalized states at

4539-456: The elements from fermium (Fm) onwards are shown in gray because they are extremely radioactive and have never been produced in bulk. Theoretical and experimental evidence suggests that these uninvestigated elements should be metals, except for oganesson (Og) which DFT calculations indicate would be a semiconductor. Metallic Network covalent Molecular covalent Single atoms Unknown Background color shows bonding of simple substances in

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4628-433: The f-block elements. They have a strong affinity for oxygen and mostly exist as relatively low-density silicate minerals. Chalcophile elements are mainly the less reactive d-block elements, and the period 4–6 p-block metals. They are usually found in (insoluble) sulfide minerals. Being denser than the lithophiles, hence sinking lower into the crust at the time of its solidification, the chalcophiles tend to be less abundant than

4717-399: The fact that Vaaler's clip was not the same as the fully developed Gem-type clip. In 1989, a giant paper clip, almost 7 m (23 ft) high, was erected on the campus of a commercial college near Oslo in honor of Vaaler, ninety years after his invention was patented. But this monument shows a Gem-type clip, not the one patented by Vaaler. The celebration of the alleged Norwegian origin of

4806-485: The flexibility and adaptability of the paper clip beyond its traditional use. Additionally, paper clips can serve as temporary bookmarks in books or documents. Their slim profile and easy placement make them useful for marking a specific page or section without causing damage or adding bulk. Paper clips can be bent into a crude but sometimes effective lock picking device. Some types of handcuffs can be unfastened using paper clips. There are two approaches. The first one

4895-724: The higher momenta) available at the highest occupied energies as sketched in the Figure. In a semiconductor like silicon or a nonmetal like strontium titanate there is an energy gap between the highest filled states of the electrons and the lowest unfilled, so no accessible states with slightly higher momenta. Consequently, semiconductors and nonmetals are poor conductors, although they can carry some current when doped with elements that introduce additional partially occupied energy states at higher temperatures. The elemental metals have electrical conductivity values of from 6.9 × 10 S /cm for manganese to 6.3 × 10 S/cm for silver . In contrast,

4984-419: The international literature on paper clips. Vaaler probably succeeded in having his design patented abroad, despite the previous existence of more useful paper clips, because patent authorities at that time were quite liberal and rewarded any marginal modification of existing inventions. Johan Vaaler began working for Alfred J. Bryns Patentkontor in Kristiania in 1892 and was later promoted to office manager,

5073-436: The known examples of half-metals are oxides , sulfides , or Heusler alloys . A semimetal is a material with a small energy overlap between the bottom of the conduction band and the top of the valence band , but they do not overlap in momentum space . Unlike a regular metal, semimetals have charge carriers of both types (holes and electrons), although the charge carriers typically occur in much smaller numbers than in

5162-482: The less electropositive metals such as BeO, Al 2 O 3 , and PbO, can display both basic and acidic properties. The latter are termed amphoteric oxides. The elements that form exclusively metallic structures under ordinary conditions are shown in yellow on the periodic table below. The remaining elements either form covalent network structures (light blue), molecular covalent structures (dark blue), or remain as single atoms (violet). Astatine (At), francium (Fr), and

5251-408: The lithophiles. On the other hand, gold is a siderophile, or iron-loving element. It does not readily form compounds with either oxygen or sulfur. At the time of the Earth's formation, and as the most noble (inert) of metallic elements, gold sank into the core due to its tendency to form high-density metallic alloys. Consequently, it is relatively rare. Some other (less) noble ones—molybdenum, rhenium,

5340-487: The market, although not yet in Norway. His version was never manufactured and never marketed because the superior Gem was already available. Long after Vaaler's death, his countrymen created a national myth based on the false assumption that the paper clip was invented by an unrecognized Norwegian genius. Norwegian dictionaries since the 1950s have mentioned Vaaler as the inventor of the paper clip, and that myth later found its way into international dictionaries and much of

5429-407: The metallic alloys in use today, the alloys of iron ( steel , stainless steel , cast iron , tool steel , alloy steel ) make up the largest proportion both by quantity and commercial value. Iron alloyed with various proportions of carbon gives low-, mid-, and high-carbon steels, with increasing carbon levels reducing ductility and toughness. The addition of silicon will produce cast irons, while

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5518-481: The modern type of paper clip was well known in 1899 at the latest, is the patent granted to William Middlebrook of Waterbury , Connecticut on April 27 of that year for a "Machine for making wire paper clips." The drawing clearly shows that the product is a perfect clip of the Gem type. The fact that Middlebrook did not mention it by name, suggests that it was already well known at the time. Since then countless variations on

5607-470: The most practical, and consequently by far the most popular. Its qualities—ease of use, gripping without tearing, and storing without tangling—have been difficult to improve upon. In the USA , National Paperclip Day is celebrated on May 29th. The Gem-type paperclip has become a symbol of inventive design , as confirmed below – although falsely – by its celebration as a Norwegian invention in 1899. More convincing

5696-401: The national biographical encyclopedia of Norway ( Norsk biografisk leksikon ) published the biography of Johan Vaaler, stating he was the inventor of the paper clip. Wire is versatile in its nature. Thus a paper clip is a useful accessory in many kinds of mechanical work, including computer work: the metal wire can be unfolded with a little force. Several devices call for a very thin rod to push

5785-401: The next two elements, polonium and astatine, which decay to bismuth or lead. The r-process is so fast it can skip this zone of instability and go on to create heavier elements such as thorium and uranium. Metals condense in planets as a result of stellar evolution and destruction processes. Stars lose much of their mass when it is ejected late in their lifetimes, and sometimes thereafter as

5874-493: The nitrogen. However, unlike most elemental metals, ceramic metals are often not particularly ductile. Their uses are widespread, for instance titanium nitride finds use in orthopedic devices and as a wear resistant coating. In many cases their utility depends upon there being effective deposition methods so they can be used as thin film coatings. There are many polymers which have metallic electrical conduction, typically associated with extended aromatic components such as in

5963-623: The older structural metals, like iron at 7.9 and copper at 8.9 g/cm . The most common lightweight metals are aluminium and magnesium alloys. Metals are typically malleable and ductile, deforming under stress without cleaving . The nondirectional nature of metallic bonding contributes to the ductility of most metallic solids, where the Peierls stress is relatively low allowing for dislocation motion, and there are also many combinations of planes and directions for plastic deformation . Due to their having close packed arrangements of atoms

6052-702: The other three metals have been developed relatively recently; due to their chemical reactivity they need electrolytic extraction processes. The alloys of aluminum, titanium, and magnesium are valued for their high strength-to-weight ratios; magnesium can also provide electromagnetic shielding . These materials are ideal for situations where high strength-to-weight ratio is more important than material cost, such as in aerospace and some automotive applications. Alloys specially designed for highly demanding applications, such as jet engines , may contain more than ten elements. Metals can be categorised by their composition, physical or chemical properties. Categories described in

6141-400: The overall scarcity of some heavier metals such as copper, they can become concentrated in economically extractable quantities as a result of mountain building, erosion, or other geological processes. Metallic elements are primarily found as lithophiles (rock-loving) or chalcophiles (ore-loving). Lithophile elements are mainly the s-block elements, the more reactive of the d-block elements, and

6230-470: The paper clip culminated in 1999, one hundred years after Vaaler submitted his application for a German patent. A commemorative stamp was issued that year, the first in a series to draw attention to Norwegian inventiveness. The background shows a facsimile of the German "Patentschrift". However, the figure in the foreground is not the paper clip depicted on that document, but the much better known "Gem". In 2005,

6319-420: The platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, and platinum), germanium, and tin—can be counted as siderophiles but only in terms of their primary occurrence in the Earth (core, mantle, and crust), rather the crust. These otherwise occur in the crust, in small quantities, chiefly as chalcophiles (less so in their native form). The rotating fluid outer core of the Earth's interior, which

6408-547: The polymers indicated in the Figure. The conduction of the aromatic regions is similar to that of graphite, so is highly directional. A half-metal is any substance that acts as a conductor to electrons of one spin orientation, but as an insulator or semiconductor to those of the opposite spin. They were first described in 1983, as an explanation for the electrical properties of manganese -based Heusler alloys . Although all half-metals are ferromagnetic (or ferrimagnetic ), most ferromagnets are not half-metals. Many of

6497-401: The production of early forms of steel; the discovery of sodium —the first light metal —in 1809; the rise of modern alloy steels ; and, since the end of World War II, the development of more sophisticated alloys. Most metals are shiny and lustrous , at least when polished, or fractured. Sheets of metal thicker than a few micrometres appear opaque, but gold leaf transmits green light. This

6586-408: The ratio between thermal and electrical conductivities is proportional to temperature, with a proportionality constant that is roughly the same for all metals. The contribution of a metal's electrons to its heat capacity and thermal conductivity, and the electrical conductivity of the metal itself can be approximately calculated from the free electron model . However, this does not take into account

6675-415: The ratio of the two components is fixed (also known as an intermetallic compound ). Most pure metals are either too soft, brittle, or chemically reactive for practical use. Combining different ratios of metals and other elements in alloys modifies the properties to produce desirable characteristics, for instance more ductile, harder, resistant to corrosion, or have a more desirable color and luster. Of all

6764-497: The sale price of the metal(s) involved make it economically feasible to mine lower concentration sources. Johan Vaaler Johan Vaaler (March 15, 1866 – March 14, 1910) was a Norwegian inventor and patent clerk . He has often erroneously been identified as the inventor of the common paper clip . Johan Vaaler was born at Aurskog-Høland in Akershus , Norway. Vaaler worked from 1892 until his death in 1910 as

6853-416: The same as cermets which are composites of a non-conducting ceramic and a conducting metal.) One set, the transition metal nitrides has significant ionic character to the bonding, so can be classified as both ceramics and metals. They have partially filled states at the Fermi level so are good thermal and electrical conductors, and there is often significant charge transfer from the transition metal atoms to

6942-413: The same theme have been patented. Some have pointed instead of rounded ends, some have the end of one loop bent slightly to make it easier to insert sheets of paper, and some have wires with undulations or barbs to get a better grip. In addition, purely aesthetic variants have been patented, clips with triangular, star, or round shapes. But the original Gem type has for more than a hundred years proved to be

7031-427: The small home market. Quite soon he must have had the disappointment of his life when he was confronted by the "Gem", which was probably introduced in Norway during his own lifetime. He is not known to have tried to contact potential manufacturers in Norway or abroad, and this lack of initiative seems to confirm that he soon learned that a superior clip already existed. His patent was allowed to expire quietly. Meanwhile,

7120-635: The subsections below include ferrous and non-ferrous metals; brittle metals and refractory metals ; white metals; heavy and light metals; base , noble , and precious metals as well as both metallic ceramics and polymers . The term "ferrous" is derived from the Latin word meaning "containing iron". This can include pure iron, such as wrought iron , or an alloy such as steel . Ferrous metals are often magnetic , but not exclusively. Non-ferrous metals and alloys lack appreciable amounts of iron. While nearly all elemental metals are malleable or ductile,

7209-474: The term base metal is contrasted with precious metal , that is, those of high economic value. Most coins today are made of base metals with low intrinsic value ; in the past, coins frequently derived their value primarily from their precious metal content; gold , silver , platinum , and palladium each have an ISO 4217 currency code. Currently they have industrial uses such as platinum and palladium in catalytic converters , are used in jewellery and also

7298-634: The term metal is often used to denote those elements which in pure form and at standard conditions are metals in the sense of electrical conduction mentioned above. The related term metallic may also be used for types of dopant atoms or alloying elements. In astronomy metal refers to all chemical elements in a star that are heavier than helium . In this sense the first four "metals" collecting in stellar cores through nucleosynthesis are carbon , nitrogen , oxygen , and neon . A star fuses lighter atoms, mostly hydrogen and helium, into heavier atoms over its lifetime. The metallicity of an astronomical object

7387-496: The upper atmosphere (including the ozone layer that limits the transmission of ultraviolet radiation). Metallic elements are often extracted from the Earth by mining ores that are rich sources of the requisite elements, such as bauxite . Ores are located by prospecting techniques, followed by the exploration and examination of deposits. Mineral sources are generally divided into surface mines , which are mined by excavation using heavy equipment, and subsurface mines . In some cases,

7476-495: Was also patented in the United States by Erlman J. Wright on July 24, 1877, patent #193,389. This clip was advertised at that time for use in fastening together loose leaves of papers, documents, periodicals, newspapers etc. The most common type of wire paper clip still in use, the Gem paper clip, was never patented, but it was most likely in production in Britain in the early 1870s by "The Gem Manufacturing Company", according to

7565-484: Was even more obvious because paper clips are called " binders " in Norwegian. Their presumed Norwegian origin was not generally known at that time, but when that widely believed story was added to the war-time experience of many patriots, it strengthened their status as national symbols. Proofs of the national pride in Vaaler's alleged invention are the postage stamp issued in 1999 and the giant paper clip erected in front of

7654-649: Was granted on June 4, 1901. Unknown to Vaaler, a more functional and practical paper clip was already in production by the British Gem Manufacturing Company Ltd, but not yet marketed in Norway. His design was inferior because it lacked the two full loops of the wire. Vaaler probably succeeded in having his design patented abroad, despite the existence of a better product, because patent authorities at that time were quite liberal and rewarded any marginal modification of earlier inventions. Several types of paper clips had been patented in

7743-423: Was not the same as the then-common Gem-type clip. In the report of the first fifty years of the patent agency, he wrote an article in which he proclaimed Vaaler to be the inventor of the common paper clip. This piece of information found its way into some Norwegian encyclopedias after World War II . Events of that war contributed greatly to the mythical status of the paper clip. Patriots wore them in their lapels as

7832-409: Was originally intended primarily for attaching tickets to fabric, although the patent recognized that it could be used to attach papers together. Fay received U.S. patent 64,088 on April 23, 1867. Although functional and practical, Fay's design along with the 50 other designs patented prior to 1899 are not considered reminiscent of the modern paperclip design known today. Another notable paper clip design

7921-481: Was soon prohibited, and people wearing them could risk severe punishment. The leading Norwegian encyclopedia mentioned the role of the paper clip as a symbol of resistance in a supplementary volume in 1952 but did not yet proclaim it a Norwegian invention. That information was added in later editions. According to the 1974 edition, the idea of using the paper clip to denote resistance originated in France . A clip worn on

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