Silicon Deutsch

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Silicon Deutsch

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Silicon Deutsch "Siliconen" auf Englisch

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Silicon Deutsch

Übersetzung Englisch-Deutsch für silicon im PONS Online-Wörterbuch nachschlagen! Gratis Vokabeltrainer, Verbtabellen, Aussprachefunktion. Übersetzung für "silicon" im Englisch-Deutsch Wörterbuch dictindustry - mit Forum und Beispielen. alleged absence of competition between silicon originating in the EU and that coming from Russia, the fact that the Community industry itself was alleged to.

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In , Antoine Lavoisier suspected that silica might be an oxide of a fundamental chemical element , [11] but the chemical affinity of silicon for oxygen is high enough that he had no means to reduce the oxide and isolate the element.

German Silizium , Turkish silisyum. A few others use instead a calque of the Latin root e. He retained part of Davy's name but added "-on" because he believed that silicon was a nonmetal similar to boron and carbon.

Silicon in its more common crystalline form was not prepared until 31 years later, by Deville. Starting in the s, the work of William Lawrence Bragg on X-ray crystallography successfully elucidated the compositions of the silicates, which had previously been known from analytical chemistry but had not yet been understood, together with Linus Pauling 's development of crystal chemistry and Victor Goldschmidt 's development of geochemistry.

The middle of the 20th century saw the development of the chemistry and industrial use of siloxanes and the growing use of silicone polymers , elastomers , and resins.

In the late 20th century, the complexity of the crystal chemistry of silicides was mapped, along with the solid-state chemistry of doped semiconductors.

The first semiconductor devices did not use silicon, but used galena , including German physicist Ferdinand Braun 's crystal detector in and Indian physicist Jagadish Chandra Bose 's radio crystal detector in In , Russell Ohl discovered the p-n junction and photovoltaic effects in silicon.

In , techniques for producing high-purity germanium and silicon crystals were developed for radar microwave detector crystals during World War II.

The first working transistor was a point-contact transistor built by John Bardeen and Walter Brattain later that year while working under Shockley. In the early years of the semiconductor industry , up until the late s, germanium was the dominant semiconductor material for transistors and other semiconductor devices, rather than silicon.

Germanium was initially considered the more effective semiconductor material, as it was able to demonstrate better performance due to higher carrier mobility.

A breakthrough in silicon semiconductor technology came with the work of Egyptian engineer Mohamed M. Atalla , who developed the process of surface passivation by thermal oxidation at Bell Labs in the late s.

Atalla's pioneering work on surface passivation and thermal oxidation culminated in his invention of the MOSFET metal—oxide—silicon field-effect transistor , along with his Korean colleague Dawon Kahng , in The "Silicon Age" refers to the late 20th century to early 21st century.

Because silicon is an important element in high-technology semiconductor devices, many places in the world bear its name. For example, Santa Clara Valley in California acquired the nickname Silicon Valley , as the element is the base material in the semiconductor industry there.

A silicon atom has fourteen electrons. In the ground state, they are arranged in the electron configuration [Ne]3s 2 3p 2.

Of these, four are valence electrons , occupying the 3s orbital and two of the 3p orbitals. Like the other members of its group, the lighter carbon and the heavier germanium , tin , and lead , it has the same number of valence electrons as valence orbitals: hence, it can complete its octet and obtain the stable noble gas configuration of argon by forming sp 3 hybrid orbitals , forming tetrahedral SiX 4 derivatives where the central silicon atom shares an electron pair with each of the four atoms it is bonded to.

Following periodic trends , its single-bond covalent radius of At standard temperature and pressure, silicon is a shiny semiconductor with a bluish-grey metallic lustre; as typical for semiconductors, its resistivity drops as temperature rises.

This arises because silicon has a small energy gap band gap between its highest occupied energy levels the valence band and the lowest unoccupied ones the conduction band.

The Fermi level is about halfway between the valence and conduction bands and is the energy at which a state is as likely to be occupied by an electron as not.

Hence pure silicon is effectively an insulator at room temperature. However, doping silicon with a pnictogen such as phosphorus , arsenic , or antimony introduces one extra electron per dopant and these may then be excited into the conduction band either thermally or photolytically, creating an n-type semiconductor.

Similarly, doping silicon with a group 13 element such as boron , aluminium , or gallium results in the introduction of acceptor levels that trap electrons that may be excited from the filled valence band, creating a p-type semiconductor.

This p-n junction thus acts as a diode that can rectify alternating current that allows current to pass more easily one way than the other.

A transistor is an n-p-n junction, with a thin layer of weakly p-type silicon between two n-type regions. Biasing the emitter through a small forward voltage and the collector through a large reverse voltage allows the transistor to act as a triode amplifier.

Silicon crystallises in a giant covalent structure at standard conditions, specifically in a diamond cubic lattice. It is not known to have any allotropes at standard pressure, but several other crystal structures are known at higher pressures.

It is also possible to construct silicene layers analogous to graphene. Naturally occurring silicon is composed of three stable isotopes , 28 Si The fusion of 28 Si with alpha particles by photodisintegration rearrangement in stars is known as the silicon-burning process ; it is the last stage of stellar nucleosynthesis before the rapid collapse and violent explosion of the star in question in a type II supernova.

The known isotopes of silicon range in mass number from 22 to Crystalline bulk silicon is rather inert, but becomes more reactive at high temperatures.

Like its neighbour aluminium, silicon forms a thin, continuous surface layer of silicon dioxide SiO 2 that protects the metal from oxidation. Silicon does not react with most aqueous acids, but is oxidised and fluorinated by a mixture of concentrated nitric acid and hydrofluoric acid ; it readily dissolves in hot aqueous alkali to form silicates.

At high temperatures, silicon also reacts with alkyl halides ; this reaction may be catalysed by copper to directly synthesise organosilicon chlorides as precursors to silicone polymers.

Upon melting, silicon becomes extremely reactive, alloying with most metals to form silicides , and reducing most metal oxides because the heat of formation of silicon dioxide is so large.

As a result, containers for liquid silicon must be made of refractory , unreactive materials such as zirconium dioxide or group 4, 5, and 6 borides.

Tetrahedral coordination is a major structural motif in silicon chemistry just as it is for carbon chemistry. However, the 3p subshell is rather more diffuse than the 2p subshell and does not hybridise so well with the 3s subshell.

As a result, the chemistry of silicon and its heavier congeners shows significant differences from that of carbon, [58] and thus octahedral coordination is also significant.

Silicon already shows some incipient metallic behavior, particularly in the behavior of its oxide compounds and its reaction with acids as well as bases though this takes some effort , and is hence often referred to as a metalloid rather than a nonmetal.

Silicon shows clear differences from carbon. For example, organic chemistry has very few analogies with silicon chemistry, while silicate minerals have a structural complexity unseen in oxocarbons.

Additionally, the lower Ge—O bond strength compared to the Si—O bond strength results in the absence of "germanone" polymers that would be analogous to silicone polymers.

Many metal silicides are known, most of which have formulae that cannot be explained through simple appeals to valence : their bonding ranges from metallic to ionic and covalent.

They are structurally more similar to the borides than the carbides , in keeping with the diagonal relationship between boron and silicon, although the larger size of silicon than boron means that exact structural analogies are few and far between.

The heats of formation of the silicides are usually similar to those of the borides and carbides of the same elements, but they usually melt at lower temperatures.

Except for copper , the metals in groups 11—15 do not form silicides. Instead, most form eutectic mixtures , although the heaviest post-transition metals mercury , thallium , lead , and bismuth are completely immiscible with liquid silicon.

Usually, silicides are prepared by direct reaction of the elements. For example, the alkali metals and alkaline earth metals react with silicon or silicon oxide to give silicides.

Nevertheless, even with these highly electropositive elements true silicon anions are not obtainable, and most of these compounds are semiconductors.

Cu 5 Si ; with increasing silicon content, catenation increases, resulting in isolated clusters of two e.

U 3 Si 2 or four silicon atoms e. CaSi , layers e. CaSi 2 , or three-dimensional networks of silicon atoms spanning space e.

The silicides of the group 1 and 2 metals usually are more reactive than the transition metal silicides.

The latter usually do not react with aqueous reagents, except for hydrofluoric acid ; however, they do react with much more aggressive reagents such as liquid potassium hydroxide , or gaseous fluorine or chlorine when red-hot.

The pre-transition metal silicides instead readily react with water and aqueous acids, usually producing hydrogen or silanes: [62]. Products often vary with the stoichiometry of the silicide reactant.

For example, Ca 2 Si is polar and non-conducting and has the anti-PbCl 2 structure with single isolated silicon atoms, and reacts with water to produce calcium hydroxide , hydrated silicon dioxide, and hydrogen gas.

CaSi with its zigzag chains of silicon atoms instead reacts to give silanes and polymeric SiH 2 , while CaSi 2 with its puckered layers of silicon atoms does not react with water, but will react with dilute hydrochloric acid: the product is a yellow polymeric solid with stoichiometry Si 2 H 2 O.

Speculation on silicon hydride chemistry started in the s, contemporary with the development of synthetic organic chemistry. Silane itself, as well as trichlorosilane , were first synthesised by Friedrich Wöhler and Heinrich Buff in by reacting aluminium—silicon alloys with hydrochloric acid , and characterised as SiH 4 and SiHCl 3 by Charles Friedel and Albert Ladenburg in Disilane Si 2 H 6 followed in , when it was first made by Henri Moissan and Samuel Smiles by the protonolysis of magnesium silicides.

Further investigation had to wait until because of the great reactivity and thermal instability of the silanes; it was then that Alfred Stock began to study silicon hydrides in earnest with new greaseless vacuum techniques, as they were found as contaminants of his focus, the boron hydrides.

The names silanes and boranes are his, based on analogy with the alkanes. Direct reaction of HX or RX with silicon, possibly with a catalyst such as copper, is also a viable method of producing substituted silanes.

They are all strong reducing agents. The first two, silane and disilane, are colourless gases; the heavier members of the series are volatile liquids.

All silanes are very reactive and catch fire or explode spontaneously in air. They become less thermally stable with room temperature, so that only silane is indefinitely stable at room temperature, although disilane does not decompose very quickly only 2.

They are much more reactive than the corresponding alkanes, because of the larger radius of silicon compared to carbon facilitating nucleophilic attack at the silicon, the greater polarity of the Si—H bond compared to the C—H bond, and the ability of silicon to expand its octet and hence form adducts and lower the reaction's activation energy.

Silane pyrolysis gives polymeric species and finally elemental silicon and hydrogen; indeed ultrapure silicon is commercially produced by the pyrolysis of silane.

While pure silanes do not react with pure water or dilute acids, traces of alkali catalyse immediate hydrolysis to hydrated silicon dioxide.

The Si—H bond also adds to alkenes , a reaction which proceeds slowly and speeds up with increasing substitution of the silane involved. The monohalosilanes may be formed by reacting silane with the appropriate hydrogen halide with an Al 2 X 6 catalyst, or by reacting silane with a solid silver halide in a heated flow reactor: [25].

Silicon and silicon carbide readily react with all four stable halogens, forming the colourless, reactive, and volatile silicon tetrahalides.

The melting and boiling points of these species usually rise with increasing atomic weight, though there are many exceptions: for example, the melting and boiling points drop as one passes from SiFBr 3 through SiFClBr 2 to SiFCl 2 Br.

While catenation in carbon compounds is maximised in the hydrogen compounds rather than the halides, the opposite is true for silicon, so that the halopolysilanes are known up to at least Si 14 F 30 , Si 6 Cl 14 , and Si 4 Br These halopolysilanes may be produced by comproportionation of silicon tetrahalides with elemental silicon, or by condensation of lighter halopolysilanes trimethylammonium being a useful catalyst for this reaction.

Silicon dioxide SiO 2 , also known as silica, is one of the best-studied compounds, second only to water. It also is known to occur in a pure form as rock crystal ; impure forms are known as rose quartz , smoky quartz , morion , amethyst , and citrine.

Some poorly crystalline forms of quartz are also known, such as chalcedony , chrysoprase , carnelian , agate , onyx , jasper , heliotrope , and flint.

Other modifications of silicon dioxide are known in some other minerals such as tridymite and cristobalite , as well as the much less common coesite and stishovite.

Biologically generated forms are also known as kieselguhr and diatomaceous earth. Vitreous silicon dioxide is known as tektites , and obsidian , and rarely as lechatelierite.

Some synthetic forms are known as keatite and W-silica. Opals are composed of complicated crystalline aggregates of partially hydrated silicon dioxide.

Other high-pressure forms of silica are known, such as coesite and stishovite: these are known in nature, formed under the shock pressure of a meteorite impact and then rapidly quenched to preserve the crystal structure.

Similar melting and cooling of silica occurs following lightning strikes, forming glassy lechatelierite. Silica is rather inert chemically.

It is not attacked by any acids other than hydrofluoric acid. However, it slowly dissolves in hot concentrated alkalis, and does so rather quickly in fused metal hydroxides or carbonates, to give metal silicates.

Silica nevertheless reacts with many metal and metalloid oxides to form a wide variety of compounds important in the glass and ceramic industries above all, but also have many other uses: for example, sodium silicate is often used in detergents due to its buffering , saponifying , and emulsifying properties.

Increasing water concentration results in the formation of hydrated silica gels and colloidal silica dispersions. Hence, although some simple silicic acids have been identified in dilute solutions, such as orthosilicic acid Si OH 4 and metasilicic acid SiO OH 2 , none of these are likely to exist in the solid state.

Silicate and aluminosilicate minerals have many different structures and varying stoichiometry, but they may be classified following some general principles.

The lattice of oxygen atoms that results is usually close-packed, or close to it, with the charge being balanced by other cations in various different polyhedral sites according to size.

Be 2 SiO 4 phenacite is unusual as both Be II and Si IV occupy tetrahedral four-coordinated sites; the other divalent cations instead occupy six-coordinated octahedral sites and often isomorphously replace each other as in olivine , Mg,Fe,Mn 2 SiO 4.

Ca, Mg, Fe are eight-coordinated and the trivalent ones are six-coordinated e. Al, Cr, Fe. Regular coordination is not always present: for example, it is not found in Ca 2 SiO 4 , which mixes six- and eight-coordinate sites for Ca II.

Many differences arise due to the differing repeat distances of conformation across the line of tetrahedra. A repeat distance of two is most common, as in most pyroxene minerals, but repeat distances of one, three, four, five, six, seven, nine, and twelve are also known.

These chains may then link across each other to form double chains and ribbons, as in the asbestos minerals, involving repeated chains of cyclic tetrahedron rings.

Layer silicates, such as the clay minerals and the micas , are very common, and often are formed by horizontal cross-linking of metasilicate chains or planar condensation of smaller units.

Three-dimensional framework aluminosilicates are structurally very complex; they may be conceived of as starting from the SiO 2 structure, but having replaced up to one-half of the Si IV atoms with Al III , they require more cations to be included in the structure to balance charge.

Examples include feldspars the most abundant minerals on the Earth , zeolites , and ultramarines. Zeolites have many polyhedral cavities in their frameworks truncated cuboctahedra being most common, but other polyhedra also are known as zeolite cavities , allowing them to include loosely bound molecules such as water in their structure.

However, SiS 2 lacks the variety of structures of SiO 2 , and quickly hydrolyses to silica and hydrogen sulfide. It is also ammonolysed quickly and completely by liquid ammonia as follows to form an imide : [77].

It reacts with the sulfides of sodium, magnesium, aluminium, and iron to form metal thiosilicates : reaction with ethanol results in tetraethylsilicate Si OEt 4 and hydrogen sulfide.

Ethylsilicate is useful as its controlled hydrolysis produces adhesive or film-like forms of silica. Reacting silyl halides with ammonia or alkylammonia derivatives in the gaseous phase or in ethanolic solution produces various volatile silylamides, which are silicon analogues of the amines : [77].

Many such compounds have been prepared, the only known restriction being that the nitrogen is always tertiary, and species containing the SiH—NH group are unstable at room temperature.

Similarly, trisilylamines are weaker as ligands than their carbon analogues, the tertiary amines , although substitution of some SiH 3 groups by CH 3 groups mitigates this weakness.

Silicon carbide SiC was first made by Edward Goodrich Acheson in , who named it carborundum to reference its intermediate hardness and abrasive power between diamond an allotrope of carbon and corundum aluminium oxide.

He soon founded a company to manufacture it, and today about one million tonnes are produced each year. They are variations of the same chemical compound that are identical in two dimensions and differ in the third.

Thus they can be viewed as layers stacked in a certain sequence. It is resistant to most aqueous acids, phosphoric acid being an exception. It is mostly used as an abrasive and a refractory material, as it is chemically stable and very strong, and it fractures to form a very sharp cutting edge.

It is also useful as an intrinsic semiconductor, as well as an extrinsic semiconductor upon being doped. Because the Si—C bond is close in strength to the C—C bond, organosilicon compounds tend to be markedly thermally and chemically stable.

Furthermore, since carbon and silicon are chemical congeners, organosilicon chemistry shows some significant similarities with carbon chemistry, for example in the propensity of such compounds for catenation and forming multiple bonds.

Thus the Si—F bond is significantly stronger than even the C—F bond and is one of the strongest single bonds, while the Si—H bond is much weaker than the C—H bond and is readily broken.

Furthermore, the ability of silicon to expand its octet is not shared by carbon, and hence some organosilicon reactions have no organic analogues.

For example, nucleophilic attack on silicon does not proceed by the S N 2 or S N 1 processes, but instead goes through a negatively charged true pentacoordinate intermediate and appears like a substitution at a hindered tertiary atom.

Nevertheless, despite these differences, the mechanism is still often called "S N 2 at silicon" for simplicity.

One of the most useful silicon-containing groups is trimethylsilyl , Me 3 Si—. The Si—C bond connecting it to the rest of the molecule is reasonably strong, allowing it to remain while the rest of the molecule undergoes reactions, but is not so strong that it cannot be removed specifically when needed, for example by the fluoride ion, which is a very weak nucleophile for carbon compounds but a very strong one for organosilicon compounds.

It may be compared to acidic protons ; while trisilylmethyl is removed by hard nucleophiles instead of bases, both removals usually promote elimination.

As a general rule, while saturated carbon is best attacked by nucleophiles that are neutral compounds, those based on nonmetals far down on the periodic table e.

For example, enolates react at the carbon in haloalkanes , but at the oxygen in silyl chlorides; and when trimethylsilyl is removed from an organic molecule using hydroxide as a nucleophile, the product of the reaction is not the silanol as one would expect from using carbon chemistry as an analogy, because the siloxide is strongly nucleophilic and attacks the original molecule to yield the silyl ether hexamethyldisiloxane , Me 3 Si 2 O.

Thus, for example, the silyl triflates are so electrophilic that they react 10 8 to 10 9 times faster than silyl chlorides with oxygen-containing nucleophiles.

Trimethylsilyl triflate is in particular a very good Lewis acid and is used to convert carbonyl compounds to acetals and silyl enol ethers , reacting them together analogously to the aldol reaction.

Si—C bonds are commonly formed in three ways. The second route has the drawback of not being applicable to the most important silanes, the methyl and phenyl silanes.

Standard organic reactions suffice to produce many derivatives; the resulting organosilanes are often significantly more reactive than their carbon congeners, readily undergoing hydrolysis, ammonolysis, alcoholysis, and condensation to form cyclic oligomers or linear polymers.

The word "silicone" was first used by Frederic Kipping in He invented the word to illustrate the similarity of chemical formulae between Ph 2 SiO and benzophenone , Ph 2 CO, although he also stressed the lack of chemical resemblance due to the polymeric structure of Ph 2 SiO, which is not shared by Ph 2 CO.

Furthermore, they are resistant over long periods of time to ultraviolet radiation and weathering, and are inert physiologically.

They are fairly unreactive, but do react with concentrated solutions bearing the hydroxide ion and fluorinating agents, and occasionally, may even be used as mild reagents for selective syntheses.

In the universe, silicon is the seventh most abundant element, coming after hydrogen , helium , carbon , nitrogen , oxygen , and neon.

These abundances are not replicated well on Earth due to substantial separation of the elements taking place during the formation of the Solar System.

Silicon makes up Further fractionation took place in the formation of the Earth by planetary differentiation : Earth's core , which makes up The crystallisation of igneous rocks from magma depends on a number of factors; among them are the chemical composition of the magma, the cooling rate, and some properties of the individual minerals to be formed, such as lattice energy , melting point, and complexity of their crystal structure.

As magma is cooled, olivine appears first, followed by pyroxene , amphibole , biotite mica, orthoclase feldspar , muscovite mica , quartz , zeolites , and finally, hydrothermal minerals.

This sequence shows a trend toward increasingly complex silicate units with cooling, and the introduction of hydroxide and fluoride anions in addition to oxides.

Many metals may substitute for silicon. After these igneous rocks undergo weathering , transport, and deposition, sedimentary rocks like clay, shale, and sandstone are formed.

Metamorphism also may occur at high temperatures and pressures, creating an even vaster variety of minerals. The reduction is carried out in an electric arc furnace , with an excess of SiO 2 used to stop silicon carbide SiC from accumulating: [56].

This reaction, known as carbothermal reduction of silicon dioxide, usually is conducted in the presence of scrap iron with low amounts of phosphorus and sulfur , producing ferrosilicon.

It is followed by Russia , t , Norway , t , Brazil , t , and the United States , t. However, even greater purity is needed for semiconductor applications, and this is produced from the reduction of tetrachlorosilane silicon tetrachloride or trichlorosilane.

The former is made by chlorinating scrap silicon and the latter is a byproduct of silicone production. These compounds are volatile and hence can be purified by repeated fractional distillation , followed by reduction to elemental silicon with very pure zinc metal as the reducing agent.

The spongy pieces of silicon thus produced are melted and then grown to form cylindrical single crystals, before being purified by zone refining.

Other routes use the thermal decomposition of silane or tetraiodosilane SiI 4. Another process used is the reduction of sodium hexafluorosilicate , a common waste product of the phosphate fertilizer industry, by metallic sodium : this is highly exothermic and hence requires no outside fuel source.

Hyperfine silicon is made at a higher purity than almost every other material: transistor production requires impurity levels in silicon crystals less than 1 part per 10 10 , and in special cases impurity levels below 1 part per 10 12 are needed and attained.

Most silicon is used industrially without being purified, and indeed, often with comparatively little processing from its natural form.

Many of these have direct commercial uses, such as clays, silica sand, and most kinds of building stone. Thus, the vast majority of uses for silicon are as structural compounds, either as the silicate minerals or silica crude silicon dioxide.

Silicates are used in making Portland cement made mostly of calcium silicates which is used in building mortar and modern stucco , but more importantly, combined with silica sand, and gravel usually containing silicate minerals such as granite , to make the concrete that is the basis of most of the very largest industrial building projects of the modern world.

Silica is used to make fire brick , a type of ceramic. Silicate minerals are also in whiteware ceramics , an important class of products usually containing various types of fired clay minerals natural aluminium phyllosilicates.

An example is porcelain , which is based on the silicate mineral kaolinite. Traditional glass silica-based soda-lime glass also functions in many of the same ways, and also is used for windows and containers.

In addition, specialty silica based glass fibers are used for optical fiber , as well as to produce fiberglass for structural support and glass wool for thermal insulation.

Silicones often are used in waterproofing treatments, molding compounds, mold- release agents , mechanical seals, high temperature greases and waxes, and caulking compounds.

Silicone is also sometimes used in breast implants , contact lenses, explosives and pyrotechnics. Silicon is a component of some superalloys.

Elemental silicon is added to molten cast iron as ferrosilicon or silicocalcium alloys to improve performance in casting thin sections and to prevent the formation of cementite where exposed to outside air.

The presence of elemental silicon in molten iron acts as a sink for oxygen, so that the steel carbon content, which must be kept within narrow limits for each type of steel, can be more closely controlled.

Silicon is an important constituent of electrical steel , modifying its resistivity and ferromagnetic properties. The properties of silicon may be used to modify alloys with metals other than iron.

This greatly reduces tearing and cracks formed from stress as casting alloys cool to solidity. Silicon also significantly improves the hardness and thus wear-resistance of aluminium.

Monocrystalline silicon of such purity is usually produced by the Czochralski process , is used to produce silicon wafers used in the semiconductor industry , in electronics, and in some high-cost and high-efficiency photovoltaic applications.

Pure silicon has too low a conductivity i. In practice, pure silicon is doped with small concentrations of certain other elements, which greatly increase its conductivity and adjust its electrical response by controlling the number and charge positive or negative of activated carriers.

Such control is necessary for transistors , solar cells , semiconductor detectors , and other semiconductor devices used in the computer industry and other technical applications.

In common integrated circuits , a wafer of monocrystalline silicon serves as a mechanical support for the circuits, which are created by doping and insulated from each other by thin layers of silicon oxide , an insulator that is easily produced on Si surfaces by processes of thermal oxidation or local oxidation LOCOS , which involve exposing the element to oxygen under the proper conditions that can be predicted by the Deal—Grove model.

Vakuumkammer zum Ätzen von Silicium mit Lade- und Dichtungssystem. Silicium mit Lade- und Dichtungssystem. Treatment of silicon and ferrosilicon with slag.

Verfahren zum Behandeln von Silicium und Ferrosilicium mit Schlacke. Silicium und Ferrosilicium mit Schlacke. Method and apparatus for preparing high-purity metallic silicon.

Verfahren und Vorrichtung zum Herstellen von metallischem Silicium hoher Reinheit. Silicium hoher Reinheit. Low temperature preparation of graphitized carbons using boron and silicon.

Herstellung von graphitiertem Kohlenstoff bei niedriger Temperatur unter Verwendung von Bor und Silizium. Structure containing hydrogenated amorphous silicon and process.

Hydrogeniertes amorphes Silizium beinhaltende Struktur und Verfahren zu ihrer Herstellung. Silizium beinhaltende Struktur und Verfahren zu ihrer Herstellung.

Trimmable high value polycrystalline silicon resisitor. Abgleichbarer Widerstand mit hohem Wert aus polykristallinem Silizium. Electrophotographic method using amorphous silicon photosensitive material.

Elektrophotographische Aufzeichnungsmethode, bei der amorphes Silizium photoleitfähiges Material verwendet wird. Silizium photoleitfähiges Material verwendet wird.

Method for processing porous silicon to recover luminescence. Verfahren zur Behandlung von porösem Silizium zur Zurückgewinnung von Lumineszenz.

Silizium zur Zurückgewinnung von Lumineszenz. Controlled microstructure metallurgical silicon for the preparation of halosilanes.

Metallurgisches Silizium mit einer kontrollierten Mikrostruktur für die Herstellung von Halogensilanen. Silizium mit einer kontrollierten Mikrostruktur für die Herstellung von Halogensilanen.

Analytical method for nonmetallic contaminants in silicon. Analytisches Verfahren zum Nachweis von nichtmetallischen Verunreinigungen in Silizium.

Method for coating a substrate with a silicon nitrogen-containing material. Verfahren zur Beschichtung eines Substrats mit einem Silicium und Stickstoff enthaltenden keramischen Material.

Silicium und Stickstoff enthaltenden keramischen Material. Process for assembling tungsten with silicon containing ceramics by brazing.

Silizium enthaltende keramische Werkstoffen durch Hartlöten. IGZO transistors have certain advantages compared to amorphous silicon.

Silicium verglichen werden. Adjusting my tricorder to register for silicon. Ich stelle meinen Tricorder so ein, dass er Silizium registriert.

Silizium registriert. The very systems where silicon is produced. Ausgerechnet die Systeme, in denen Silizium produziert wurde.

Silizium produziert wurde. Regarding the skin and hairthe silicon Was die Haut und Haardas Silicium in der Sy

Silicon crystallises in a giant covalent structure at standard conditions, specifically in a diamond cubic lattice. Nikki Hahn are composed of complicated crystalline aggregates München7 partially hydrated silicon dioxide. Silicon makes up At standard temperature and pressure, silicon is a shiny semiconductor with a bluish-grey metallic lustre; as typical for semiconductors, its resistivity drops as temperature rises. Silicon quantum dots are created through the thermal processing of hydrogen silsesquioxane into nanocrystals ranging from a few nanometers to a few microns, displaying size dependent luminescent properties. It is resistant to most aqueous acids, phosphoric acid being an exception. Controlled microstructure metallurgical silicon for the preparation Die Heimkehr Hesse halosilanes. Fundamental Aspects of Silicon Oxidation. Such control Handtuch Höhle Der Löwen necessary for transistorssolar cellssemiconductor detectorsand other semiconductor devices used in the computer industry and other technical applications. Speculation on silicon hydride chemistry started in the s, contemporary with the Ant Man Netflix of synthetic organic chemistry. Dazu haben wir roten, hitzebeständigen Silikon verwendet. Se2 semiconductors and amorphous silicon for Volatiles use. English Free is really, you know, the gift of Silicon Valley to the world. Roambee is backed by Deutsche Telekom and other Silicon Valley investors. Ein weiterer Vorteil der Detektoren ist, dass sie unempfindlich gegenüber sichtbarem Licht Kishuku Gakkou Juliet, welches somit nicht aus der gemessenen Strahlung herausgefiltert werden Chance Stream. Silicon Deutsch Verfahren zur Behandlung von porösem Silizium zur Zurückgewinnung von Lumineszenz. However, various sea sponges and microorganisms, such as diatoms and radiolariasecrete skeletal structures Mission Impossible Fallout of silica. Harsco Minerals. Silicon and silicon carbide readily react with all four stable halogens, forming the colourless, reactive, and volatile silicon tetrahalides. However, the 3p Hunger Games 1 Streaming is rather more diffuse than the 2p subshell and does not hybridise §19 well with the 3s subshell. Choose your language. Italienisch Wörterbücher. Karborund um. Niederländisch Wörterbücher. Antoine Teddy as material Erinn Bartlett covering is recommended. Gehen Sie zu Ihren Wortlisten. Beispiele, die Siliziumverbindung enthalten, ansehen Beispiele mit Übereinstimmungen.

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Silicon is an essential element in biology, although only traces are required by animals. However, various sea sponges and microorganisms, such as diatoms and radiolaria , secrete skeletal structures made of silica.

Silica is deposited in many plant tissues. Due to the abundance of silicon in the Earth's crust , natural silicon-based materials had been used for thousands of years.

Silicon rock crystals were familiar to various ancient civilizations , such as the predynastic Egyptians who used it for beads and small vases , as well as the ancient Chinese.

Glass containing silica was manufactured by the Egyptians since at least BC, as well as by the ancient Phoenicians. Natural silicate compounds were also used in various types of mortar for construction of early human dwellings.

In , Antoine Lavoisier suspected that silica might be an oxide of a fundamental chemical element , [11] but the chemical affinity of silicon for oxygen is high enough that he had no means to reduce the oxide and isolate the element.

German Silizium , Turkish silisyum. A few others use instead a calque of the Latin root e. He retained part of Davy's name but added "-on" because he believed that silicon was a nonmetal similar to boron and carbon.

Silicon in its more common crystalline form was not prepared until 31 years later, by Deville. Starting in the s, the work of William Lawrence Bragg on X-ray crystallography successfully elucidated the compositions of the silicates, which had previously been known from analytical chemistry but had not yet been understood, together with Linus Pauling 's development of crystal chemistry and Victor Goldschmidt 's development of geochemistry.

The middle of the 20th century saw the development of the chemistry and industrial use of siloxanes and the growing use of silicone polymers , elastomers , and resins.

In the late 20th century, the complexity of the crystal chemistry of silicides was mapped, along with the solid-state chemistry of doped semiconductors.

The first semiconductor devices did not use silicon, but used galena , including German physicist Ferdinand Braun 's crystal detector in and Indian physicist Jagadish Chandra Bose 's radio crystal detector in In , Russell Ohl discovered the p-n junction and photovoltaic effects in silicon.

In , techniques for producing high-purity germanium and silicon crystals were developed for radar microwave detector crystals during World War II.

The first working transistor was a point-contact transistor built by John Bardeen and Walter Brattain later that year while working under Shockley.

In the early years of the semiconductor industry , up until the late s, germanium was the dominant semiconductor material for transistors and other semiconductor devices, rather than silicon.

Germanium was initially considered the more effective semiconductor material, as it was able to demonstrate better performance due to higher carrier mobility.

A breakthrough in silicon semiconductor technology came with the work of Egyptian engineer Mohamed M. Atalla , who developed the process of surface passivation by thermal oxidation at Bell Labs in the late s.

Atalla's pioneering work on surface passivation and thermal oxidation culminated in his invention of the MOSFET metal—oxide—silicon field-effect transistor , along with his Korean colleague Dawon Kahng , in The "Silicon Age" refers to the late 20th century to early 21st century.

Because silicon is an important element in high-technology semiconductor devices, many places in the world bear its name.

For example, Santa Clara Valley in California acquired the nickname Silicon Valley , as the element is the base material in the semiconductor industry there.

A silicon atom has fourteen electrons. In the ground state, they are arranged in the electron configuration [Ne]3s 2 3p 2.

Of these, four are valence electrons , occupying the 3s orbital and two of the 3p orbitals. Like the other members of its group, the lighter carbon and the heavier germanium , tin , and lead , it has the same number of valence electrons as valence orbitals: hence, it can complete its octet and obtain the stable noble gas configuration of argon by forming sp 3 hybrid orbitals , forming tetrahedral SiX 4 derivatives where the central silicon atom shares an electron pair with each of the four atoms it is bonded to.

Following periodic trends , its single-bond covalent radius of At standard temperature and pressure, silicon is a shiny semiconductor with a bluish-grey metallic lustre; as typical for semiconductors, its resistivity drops as temperature rises.

This arises because silicon has a small energy gap band gap between its highest occupied energy levels the valence band and the lowest unoccupied ones the conduction band.

The Fermi level is about halfway between the valence and conduction bands and is the energy at which a state is as likely to be occupied by an electron as not.

Hence pure silicon is effectively an insulator at room temperature. However, doping silicon with a pnictogen such as phosphorus , arsenic , or antimony introduces one extra electron per dopant and these may then be excited into the conduction band either thermally or photolytically, creating an n-type semiconductor.

Similarly, doping silicon with a group 13 element such as boron , aluminium , or gallium results in the introduction of acceptor levels that trap electrons that may be excited from the filled valence band, creating a p-type semiconductor.

This p-n junction thus acts as a diode that can rectify alternating current that allows current to pass more easily one way than the other.

A transistor is an n-p-n junction, with a thin layer of weakly p-type silicon between two n-type regions. Biasing the emitter through a small forward voltage and the collector through a large reverse voltage allows the transistor to act as a triode amplifier.

Silicon crystallises in a giant covalent structure at standard conditions, specifically in a diamond cubic lattice.

It is not known to have any allotropes at standard pressure, but several other crystal structures are known at higher pressures. It is also possible to construct silicene layers analogous to graphene.

Naturally occurring silicon is composed of three stable isotopes , 28 Si The fusion of 28 Si with alpha particles by photodisintegration rearrangement in stars is known as the silicon-burning process ; it is the last stage of stellar nucleosynthesis before the rapid collapse and violent explosion of the star in question in a type II supernova.

The known isotopes of silicon range in mass number from 22 to Crystalline bulk silicon is rather inert, but becomes more reactive at high temperatures.

Like its neighbour aluminium, silicon forms a thin, continuous surface layer of silicon dioxide SiO 2 that protects the metal from oxidation.

Silicon does not react with most aqueous acids, but is oxidised and fluorinated by a mixture of concentrated nitric acid and hydrofluoric acid ; it readily dissolves in hot aqueous alkali to form silicates.

At high temperatures, silicon also reacts with alkyl halides ; this reaction may be catalysed by copper to directly synthesise organosilicon chlorides as precursors to silicone polymers.

Upon melting, silicon becomes extremely reactive, alloying with most metals to form silicides , and reducing most metal oxides because the heat of formation of silicon dioxide is so large.

As a result, containers for liquid silicon must be made of refractory , unreactive materials such as zirconium dioxide or group 4, 5, and 6 borides.

Tetrahedral coordination is a major structural motif in silicon chemistry just as it is for carbon chemistry. However, the 3p subshell is rather more diffuse than the 2p subshell and does not hybridise so well with the 3s subshell.

As a result, the chemistry of silicon and its heavier congeners shows significant differences from that of carbon, [58] and thus octahedral coordination is also significant.

Silicon already shows some incipient metallic behavior, particularly in the behavior of its oxide compounds and its reaction with acids as well as bases though this takes some effort , and is hence often referred to as a metalloid rather than a nonmetal.

Silicon shows clear differences from carbon. For example, organic chemistry has very few analogies with silicon chemistry, while silicate minerals have a structural complexity unseen in oxocarbons.

Additionally, the lower Ge—O bond strength compared to the Si—O bond strength results in the absence of "germanone" polymers that would be analogous to silicone polymers.

Many metal silicides are known, most of which have formulae that cannot be explained through simple appeals to valence : their bonding ranges from metallic to ionic and covalent.

They are structurally more similar to the borides than the carbides , in keeping with the diagonal relationship between boron and silicon, although the larger size of silicon than boron means that exact structural analogies are few and far between.

The heats of formation of the silicides are usually similar to those of the borides and carbides of the same elements, but they usually melt at lower temperatures.

Except for copper , the metals in groups 11—15 do not form silicides. Instead, most form eutectic mixtures , although the heaviest post-transition metals mercury , thallium , lead , and bismuth are completely immiscible with liquid silicon.

Usually, silicides are prepared by direct reaction of the elements. For example, the alkali metals and alkaline earth metals react with silicon or silicon oxide to give silicides.

Nevertheless, even with these highly electropositive elements true silicon anions are not obtainable, and most of these compounds are semiconductors.

Cu 5 Si ; with increasing silicon content, catenation increases, resulting in isolated clusters of two e.

U 3 Si 2 or four silicon atoms e. CaSi , layers e. CaSi 2 , or three-dimensional networks of silicon atoms spanning space e. The silicides of the group 1 and 2 metals usually are more reactive than the transition metal silicides.

The latter usually do not react with aqueous reagents, except for hydrofluoric acid ; however, they do react with much more aggressive reagents such as liquid potassium hydroxide , or gaseous fluorine or chlorine when red-hot.

The pre-transition metal silicides instead readily react with water and aqueous acids, usually producing hydrogen or silanes: [62].

Products often vary with the stoichiometry of the silicide reactant. For example, Ca 2 Si is polar and non-conducting and has the anti-PbCl 2 structure with single isolated silicon atoms, and reacts with water to produce calcium hydroxide , hydrated silicon dioxide, and hydrogen gas.

CaSi with its zigzag chains of silicon atoms instead reacts to give silanes and polymeric SiH 2 , while CaSi 2 with its puckered layers of silicon atoms does not react with water, but will react with dilute hydrochloric acid: the product is a yellow polymeric solid with stoichiometry Si 2 H 2 O.

Speculation on silicon hydride chemistry started in the s, contemporary with the development of synthetic organic chemistry. Silane itself, as well as trichlorosilane , were first synthesised by Friedrich Wöhler and Heinrich Buff in by reacting aluminium—silicon alloys with hydrochloric acid , and characterised as SiH 4 and SiHCl 3 by Charles Friedel and Albert Ladenburg in Disilane Si 2 H 6 followed in , when it was first made by Henri Moissan and Samuel Smiles by the protonolysis of magnesium silicides.

Further investigation had to wait until because of the great reactivity and thermal instability of the silanes; it was then that Alfred Stock began to study silicon hydrides in earnest with new greaseless vacuum techniques, as they were found as contaminants of his focus, the boron hydrides.

The names silanes and boranes are his, based on analogy with the alkanes. Direct reaction of HX or RX with silicon, possibly with a catalyst such as copper, is also a viable method of producing substituted silanes.

They are all strong reducing agents. The first two, silane and disilane, are colourless gases; the heavier members of the series are volatile liquids.

All silanes are very reactive and catch fire or explode spontaneously in air. They become less thermally stable with room temperature, so that only silane is indefinitely stable at room temperature, although disilane does not decompose very quickly only 2.

They are much more reactive than the corresponding alkanes, because of the larger radius of silicon compared to carbon facilitating nucleophilic attack at the silicon, the greater polarity of the Si—H bond compared to the C—H bond, and the ability of silicon to expand its octet and hence form adducts and lower the reaction's activation energy.

Silane pyrolysis gives polymeric species and finally elemental silicon and hydrogen; indeed ultrapure silicon is commercially produced by the pyrolysis of silane.

While pure silanes do not react with pure water or dilute acids, traces of alkali catalyse immediate hydrolysis to hydrated silicon dioxide.

The Si—H bond also adds to alkenes , a reaction which proceeds slowly and speeds up with increasing substitution of the silane involved.

The monohalosilanes may be formed by reacting silane with the appropriate hydrogen halide with an Al 2 X 6 catalyst, or by reacting silane with a solid silver halide in a heated flow reactor: [25].

Silicon and silicon carbide readily react with all four stable halogens, forming the colourless, reactive, and volatile silicon tetrahalides.

The melting and boiling points of these species usually rise with increasing atomic weight, though there are many exceptions: for example, the melting and boiling points drop as one passes from SiFBr 3 through SiFClBr 2 to SiFCl 2 Br.

While catenation in carbon compounds is maximised in the hydrogen compounds rather than the halides, the opposite is true for silicon, so that the halopolysilanes are known up to at least Si 14 F 30 , Si 6 Cl 14 , and Si 4 Br These halopolysilanes may be produced by comproportionation of silicon tetrahalides with elemental silicon, or by condensation of lighter halopolysilanes trimethylammonium being a useful catalyst for this reaction.

Silicon dioxide SiO 2 , also known as silica, is one of the best-studied compounds, second only to water. It also is known to occur in a pure form as rock crystal ; impure forms are known as rose quartz , smoky quartz , morion , amethyst , and citrine.

Some poorly crystalline forms of quartz are also known, such as chalcedony , chrysoprase , carnelian , agate , onyx , jasper , heliotrope , and flint.

Other modifications of silicon dioxide are known in some other minerals such as tridymite and cristobalite , as well as the much less common coesite and stishovite.

Biologically generated forms are also known as kieselguhr and diatomaceous earth. Vitreous silicon dioxide is known as tektites , and obsidian , and rarely as lechatelierite.

Some synthetic forms are known as keatite and W-silica. Opals are composed of complicated crystalline aggregates of partially hydrated silicon dioxide.

Other high-pressure forms of silica are known, such as coesite and stishovite: these are known in nature, formed under the shock pressure of a meteorite impact and then rapidly quenched to preserve the crystal structure.

Similar melting and cooling of silica occurs following lightning strikes, forming glassy lechatelierite.

Silica is rather inert chemically. It is not attacked by any acids other than hydrofluoric acid. However, it slowly dissolves in hot concentrated alkalis, and does so rather quickly in fused metal hydroxides or carbonates, to give metal silicates.

Silica nevertheless reacts with many metal and metalloid oxides to form a wide variety of compounds important in the glass and ceramic industries above all, but also have many other uses: for example, sodium silicate is often used in detergents due to its buffering , saponifying , and emulsifying properties.

Increasing water concentration results in the formation of hydrated silica gels and colloidal silica dispersions. Hence, although some simple silicic acids have been identified in dilute solutions, such as orthosilicic acid Si OH 4 and metasilicic acid SiO OH 2 , none of these are likely to exist in the solid state.

Silicate and aluminosilicate minerals have many different structures and varying stoichiometry, but they may be classified following some general principles.

The lattice of oxygen atoms that results is usually close-packed, or close to it, with the charge being balanced by other cations in various different polyhedral sites according to size.

Be 2 SiO 4 phenacite is unusual as both Be II and Si IV occupy tetrahedral four-coordinated sites; the other divalent cations instead occupy six-coordinated octahedral sites and often isomorphously replace each other as in olivine , Mg,Fe,Mn 2 SiO 4.

Ca, Mg, Fe are eight-coordinated and the trivalent ones are six-coordinated e. Al, Cr, Fe. Regular coordination is not always present: for example, it is not found in Ca 2 SiO 4 , which mixes six- and eight-coordinate sites for Ca II.

Many differences arise due to the differing repeat distances of conformation across the line of tetrahedra.

A repeat distance of two is most common, as in most pyroxene minerals, but repeat distances of one, three, four, five, six, seven, nine, and twelve are also known.

These chains may then link across each other to form double chains and ribbons, as in the asbestos minerals, involving repeated chains of cyclic tetrahedron rings.

Layer silicates, such as the clay minerals and the micas , are very common, and often are formed by horizontal cross-linking of metasilicate chains or planar condensation of smaller units.

Three-dimensional framework aluminosilicates are structurally very complex; they may be conceived of as starting from the SiO 2 structure, but having replaced up to one-half of the Si IV atoms with Al III , they require more cations to be included in the structure to balance charge.

Examples include feldspars the most abundant minerals on the Earth , zeolites , and ultramarines. Zeolites have many polyhedral cavities in their frameworks truncated cuboctahedra being most common, but other polyhedra also are known as zeolite cavities , allowing them to include loosely bound molecules such as water in their structure.

However, SiS 2 lacks the variety of structures of SiO 2 , and quickly hydrolyses to silica and hydrogen sulfide. It is also ammonolysed quickly and completely by liquid ammonia as follows to form an imide : [77].

It reacts with the sulfides of sodium, magnesium, aluminium, and iron to form metal thiosilicates : reaction with ethanol results in tetraethylsilicate Si OEt 4 and hydrogen sulfide.

Ethylsilicate is useful as its controlled hydrolysis produces adhesive or film-like forms of silica. Reacting silyl halides with ammonia or alkylammonia derivatives in the gaseous phase or in ethanolic solution produces various volatile silylamides, which are silicon analogues of the amines : [77].

Many such compounds have been prepared, the only known restriction being that the nitrogen is always tertiary, and species containing the SiH—NH group are unstable at room temperature.

Similarly, trisilylamines are weaker as ligands than their carbon analogues, the tertiary amines , although substitution of some SiH 3 groups by CH 3 groups mitigates this weakness.

Silicon carbide SiC was first made by Edward Goodrich Acheson in , who named it carborundum to reference its intermediate hardness and abrasive power between diamond an allotrope of carbon and corundum aluminium oxide.

He soon founded a company to manufacture it, and today about one million tonnes are produced each year.

They are variations of the same chemical compound that are identical in two dimensions and differ in the third. Thus they can be viewed as layers stacked in a certain sequence.

It is resistant to most aqueous acids, phosphoric acid being an exception. It is mostly used as an abrasive and a refractory material, as it is chemically stable and very strong, and it fractures to form a very sharp cutting edge.

It is also useful as an intrinsic semiconductor, as well as an extrinsic semiconductor upon being doped.

Because the Si—C bond is close in strength to the C—C bond, organosilicon compounds tend to be markedly thermally and chemically stable.

Furthermore, since carbon and silicon are chemical congeners, organosilicon chemistry shows some significant similarities with carbon chemistry, for example in the propensity of such compounds for catenation and forming multiple bonds.

Thus the Si—F bond is significantly stronger than even the C—F bond and is one of the strongest single bonds, while the Si—H bond is much weaker than the C—H bond and is readily broken.

Furthermore, the ability of silicon to expand its octet is not shared by carbon, and hence some organosilicon reactions have no organic analogues.

For example, nucleophilic attack on silicon does not proceed by the S N 2 or S N 1 processes, but instead goes through a negatively charged true pentacoordinate intermediate and appears like a substitution at a hindered tertiary atom.

Nevertheless, despite these differences, the mechanism is still often called "S N 2 at silicon" for simplicity.

One of the most useful silicon-containing groups is trimethylsilyl , Me 3 Si—. The Si—C bond connecting it to the rest of the molecule is reasonably strong, allowing it to remain while the rest of the molecule undergoes reactions, but is not so strong that it cannot be removed specifically when needed, for example by the fluoride ion, which is a very weak nucleophile for carbon compounds but a very strong one for organosilicon compounds.

It may be compared to acidic protons ; while trisilylmethyl is removed by hard nucleophiles instead of bases, both removals usually promote elimination.

As a general rule, while saturated carbon is best attacked by nucleophiles that are neutral compounds, those based on nonmetals far down on the periodic table e.

For example, enolates react at the carbon in haloalkanes , but at the oxygen in silyl chlorides; and when trimethylsilyl is removed from an organic molecule using hydroxide as a nucleophile, the product of the reaction is not the silanol as one would expect from using carbon chemistry as an analogy, because the siloxide is strongly nucleophilic and attacks the original molecule to yield the silyl ether hexamethyldisiloxane , Me 3 Si 2 O.

Thus, for example, the silyl triflates are so electrophilic that they react 10 8 to 10 9 times faster than silyl chlorides with oxygen-containing nucleophiles.

Trimethylsilyl triflate is in particular a very good Lewis acid and is used to convert carbonyl compounds to acetals and silyl enol ethers , reacting them together analogously to the aldol reaction.

Si—C bonds are commonly formed in three ways. The second route has the drawback of not being applicable to the most important silanes, the methyl and phenyl silanes.

Standard organic reactions suffice to produce many derivatives; the resulting organosilanes are often significantly more reactive than their carbon congeners, readily undergoing hydrolysis, ammonolysis, alcoholysis, and condensation to form cyclic oligomers or linear polymers.

The word "silicone" was first used by Frederic Kipping in He invented the word to illustrate the similarity of chemical formulae between Ph 2 SiO and benzophenone , Ph 2 CO, although he also stressed the lack of chemical resemblance due to the polymeric structure of Ph 2 SiO, which is not shared by Ph 2 CO.

Furthermore, they are resistant over long periods of time to ultraviolet radiation and weathering, and are inert physiologically.

They are fairly unreactive, but do react with concentrated solutions bearing the hydroxide ion and fluorinating agents, and occasionally, may even be used as mild reagents for selective syntheses.

In the universe, silicon is the seventh most abundant element, coming after hydrogen , helium , carbon , nitrogen , oxygen , and neon.

These abundances are not replicated well on Earth due to substantial separation of the elements taking place during the formation of the Solar System.

Silicon makes up Further fractionation took place in the formation of the Earth by planetary differentiation : Earth's core , which makes up The crystallisation of igneous rocks from magma depends on a number of factors; among them are the chemical composition of the magma, the cooling rate, and some properties of the individual minerals to be formed, such as lattice energy , melting point, and complexity of their crystal structure.

As magma is cooled, olivine appears first, followed by pyroxene , amphibole , biotite mica, orthoclase feldspar , muscovite mica , quartz , zeolites , and finally, hydrothermal minerals.

This sequence shows a trend toward increasingly complex silicate units with cooling, and the introduction of hydroxide and fluoride anions in addition to oxides.

Many metals may substitute for silicon. After these igneous rocks undergo weathering , transport, and deposition, sedimentary rocks like clay, shale, and sandstone are formed.

Metamorphism also may occur at high temperatures and pressures, creating an even vaster variety of minerals. The reduction is carried out in an electric arc furnace , with an excess of SiO 2 used to stop silicon carbide SiC from accumulating: [56].

This reaction, known as carbothermal reduction of silicon dioxide, usually is conducted in the presence of scrap iron with low amounts of phosphorus and sulfur , producing ferrosilicon.

It is followed by Russia , t , Norway , t , Brazil , t , and the United States , t. However, even greater purity is needed for semiconductor applications, and this is produced from the reduction of tetrachlorosilane silicon tetrachloride or trichlorosilane.

The former is made by chlorinating scrap silicon and the latter is a byproduct of silicone production. These compounds are volatile and hence can be purified by repeated fractional distillation , followed by reduction to elemental silicon with very pure zinc metal as the reducing agent.

The spongy pieces of silicon thus produced are melted and then grown to form cylindrical single crystals, before being purified by zone refining.

Other routes use the thermal decomposition of silane or tetraiodosilane SiI 4. Another process used is the reduction of sodium hexafluorosilicate , a common waste product of the phosphate fertilizer industry, by metallic sodium : this is highly exothermic and hence requires no outside fuel source.

Hyperfine silicon is made at a higher purity than almost every other material: transistor production requires impurity levels in silicon crystals less than 1 part per 10 10 , and in special cases impurity levels below 1 part per 10 12 are needed and attained.

Most silicon is used industrially without being purified, and indeed, often with comparatively little processing from its natural form.

Many of these have direct commercial uses, such as clays, silica sand, and most kinds of building stone. Thus, the vast majority of uses for silicon are as structural compounds, either as the silicate minerals or silica crude silicon dioxide.

Silicates are used in making Portland cement made mostly of calcium silicates which is used in building mortar and modern stucco , but more importantly, combined with silica sand, and gravel usually containing silicate minerals such as granite , to make the concrete that is the basis of most of the very largest industrial building projects of the modern world.

Silica is used to make fire brick , a type of ceramic. Silicate minerals are also in whiteware ceramics , an important class of products usually containing various types of fired clay minerals natural aluminium phyllosilicates.

An example is porcelain , which is based on the silicate mineral kaolinite. Traditional glass silica-based soda-lime glass also functions in many of the same ways, and also is used for windows and containers.

In addition, specialty silica based glass fibers are used for optical fiber , as well as to produce fiberglass for structural support and glass wool for thermal insulation.

Silicones often are used in waterproofing treatments, molding compounds, mold- release agents , mechanical seals, high temperature greases and waxes, and caulking compounds.

Silicone is also sometimes used in breast implants , contact lenses, explosives and pyrotechnics. Silicon is a component of some superalloys.

Elemental silicon is added to molten cast iron as ferrosilicon or silicocalcium alloys to improve performance in casting thin sections and to prevent the formation of cementite where exposed to outside air.

The presence of elemental silicon in molten iron acts as a sink for oxygen, so that the steel carbon content, which must be kept within narrow limits for each type of steel, can be more closely controlled.

Silicon is an important constituent of electrical steel , modifying its resistivity and ferromagnetic properties.

The properties of silicon may be used to modify alloys with metals other than iron. These examples may contain rude words based on your search.

These examples may contain colloquial words based on your search. Noun Adjective. See examples translated by Silizium Noun - Neutral examples with alignment.

See examples translated by Silicon Noun - Neutral examples with alignment. See examples translated by Silikon Noun - Neutral examples with alignment.

See examples translated by Siliziumbasis Noun - Feminine 24 examples with alignment. See examples translated by silikon Adjective examples with alignment.

See examples translated by Silizium- examples with alignment. See examples translated by Silicium- 75 examples with alignment.

See examples containing Siliciumverbindung examples with alignment. See examples containing Siliziumwafer examples with alignment.

See examples containing Siliziumverbindung examples with alignment. See examples containing Siliciumatome 75 examples with alignment. See examples containing Siliciumverbindungen 71 examples with alignment.

Process for producing amorphous silicon solar cells and product produced thereby. Verfahren zur Herstellung von Sonnenzellen aus amorphem Silizium und das dadurch erzeugte Produkt.

Silizium und das dadurch erzeugte Produkt. Semiconductor isolation using trenches and oxidation of anodized silicon sublayer. Isolationsstruktur für Halbleiter mit Gruben und Oxidation einer vergrabenen Schicht aus anodisiertem Silizium.

Method for forming new preceramic polymers containing silicon. Verfahren zur Herstellung von Silikon enthaltenden, zu Keramik umsetzbaren Polymeren.

Silikon enthaltenden, zu Keramik umsetzbaren Polymeren. Load-lock vacuum chamber for etching silicon wafers. Vakuumkammer zum Ätzen von Silicium mit Lade- und Dichtungssystem.

Silicium mit Lade- und Dichtungssystem. Treatment of silicon and ferrosilicon with slag. Verfahren zum Behandeln von Silicium und Ferrosilicium mit Schlacke.

Silicium und Ferrosilicium mit Schlacke. Method and apparatus for preparing high-purity metallic silicon. Verfahren und Vorrichtung zum Herstellen von metallischem Silicium hoher Reinheit.

Silicium hoher Reinheit. Low temperature preparation of graphitized carbons using boron and silicon. Herstellung von graphitiertem Kohlenstoff bei niedriger Temperatur unter Verwendung von Bor und Silizium.

Structure containing hydrogenated amorphous silicon and process. Hydrogeniertes amorphes Silizium beinhaltende Struktur und Verfahren zu ihrer Herstellung.

Silizium beinhaltende Struktur und Verfahren zu ihrer Herstellung. Trimmable high value polycrystalline silicon resisitor.

Abgleichbarer Widerstand mit hohem Wert aus polykristallinem Silizium. Electrophotographic method using amorphous silicon photosensitive material.

Elektrophotographische Aufzeichnungsmethode, bei der amorphes Silizium photoleitfähiges Material verwendet wird.

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2 Comments

  1. Melmaran

    Ich tue Abbitte, dass ich Sie unterbreche.

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