Manual Functional Molecular Silicon Compounds I: Regular Oxidation States

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For clarity, I would use sterical considerations. Going from here, only two simple phases with no dangling bonds can be formed, based on diamond structure. Since your question is a school-level question, I think the answer is as follows. Though carbon and silicon have similar electron configurations in their valence orbitals, silicon is one shell higher than carbon.

That makes the bonding energies different. In the vapour phase it is a diatomic molecule. Sign up to join this community. The best answers are voted up and rise to the top.

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Home Questions Tags Users Unanswered. Does SiO compound exist? Ask Question. Asked 3 years, 8 months ago. Active 9 months ago. Viewed 4k times. Mithoron 3, 8 8 gold badges 29 29 silver badges 47 47 bronze badges. Deborah L. Laura Turculet,, Jay D. Feldman, and, T. Organometallics , 23 10 , Mork and, T. Journal of the American Chemical Society , 13 , Glaser,, Paulus W.

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Angewandte Chemie , 22 , Angewandte Chemie International Edition , 56 22 , Shigeyoshi Inoue. Meg E. Fasulo, T. Journal of Organometallic Chemistry , 6 , European Journal of Organic Chemistry , 9 , Zark, A.

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Mitra, D. Haase, W. Saak, R. West, T. Journal of Organometallic Chemistry , 3 , Tanski, Rory Waterman. Insertion reactions involving a triamidoamine-supported zirconium complex. Dalton Transactions , 39 38 , Chemistry - A European Journal , 15 43 , Angewandte Chemie International Edition , 48 9 , Angewandte Chemie , 9 , Journal of Organometallic Chemistry , 17 , Peters, J.

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Ligands, Reagents, and Methods in Organometallic Synthesis. Catherine E. 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 : [75]. 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.


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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: [55]. 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 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. 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.

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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.

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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.

Silicon has become the most popular material for both high power semiconductors and integrated circuits because it can withstand the highest temperatures and greatest electrical activity without suffering avalanche breakdown an electron avalanche is created when heat produces free electrons and holes, which in turn pass more current, which produces more heat. In addition, the insulating oxide of silicon is not soluble in water, which gives it an advantage over germanium an element with similar properties which can also be used in semiconductor devices in certain fabrication techniques.

Monocrystalline silicon is expensive to produce, and is usually justified only in production of integrated circuits, where tiny crystal imperfections can interfere with tiny circuit paths. For other uses, other types of pure silicon may be employed. These include hydrogenated amorphous silicon and upgraded metallurgical-grade silicon UMG-Si used in the production of low-cost, large-area electronics in applications such as liquid crystal displays and of large-area, low-cost, thin-film solar cells.

Such semiconductor grades of silicon are either slightly less pure or polycrystalline rather than monocrystalline, and are produced in comparable quantities as the monocrystalline silicon: 75, to , metric tons per year. The market for the lesser grade is growing more quickly than for monocrystalline silicon.

By , polycrystalline silicon production, used mostly in solar cells, was projected to reach , metric tons per year, while monocrystalline semiconductor grade silicon was expected to remain less than 50, tons per year.

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Although silicon is readily available in the form of silicates , very few organisms use it directly. Diatoms , radiolaria , and siliceous sponges use biogenic silica as a structural material for their skeletons. In more advanced plants, the silica phytoliths opal phytoliths are rigid microscopic bodies occurring in the cell; some plants, for example rice , need silicon for their growth. There is some evidence that silicon is important to human health for their nail, hair, bone, and skin tissues, [99] for example, in studies that demonstrate that premenopausal women with higher dietary silicon intake have higher bone density , and that silicon supplementation can increase bone volume and density in patients with osteoporosis.

People may be exposed to elemental silicon in the workplace by breathing it in, swallowing it, or having contact with the skin or eye. In the latter two cases, silicon poses a slight hazard as an irritant. It is hazardous if inhaled. From Wikipedia, the free encyclopedia. Chemical element with atomic number This article is about the chemical element. For other uses, see Silicon disambiguation. Not to be confused with the silicon-containing synthetic polymer silicone. For other uses, see Element 14 disambiguation.

Main article: Isotopes of silicon. Main articles: Silicide and Binary compounds of silicon. Main article: Silanes. Main article: Silicate minerals. Main article: Organosilicon. Main article: Silicone. Main article: Semiconductor device fabrication. Further information: Semiconductor industry. CRC Press. Journal of Microelectromechanical Systems. Other elements isolated with the aid of potassium and sodium: beryllium, boron, silicon, and aluminum". Journal of Chemical Education.

Bibcode : JChEd Russian Journal of Applied Chemistry. Plant Anatomy. Part 1 Cells and Tissues 2nd ed. London: Edward Arnold. Encyclopedia Britannica. Retrieved 22 August About these "elements", Lavoisier speculates: "We are probably only acquainted as yet with a part of the metallic substances existing in nature, as all those which have a stronger affinity to oxygen than carbon possesses, are incapable, hitherto, of being reduced to a metallic state, and consequently, being only presented to our observation under the form of oxyds, are confounded with earths.

It is extremely probable that barytes, which we have just now arranged with earths, is in this situation; for in many experiments it exhibits properties nearly approaching to those of metallic bodies. It is even possible that all the substances we call earths may be only metallic oxyds, irreducible by any hitherto known process. Edinburgh, Scotland: William Creech, Retrieved London: Baldwin, Cradock, and Joy, , vol. From p. But as there is not the smallest evidence for its metallic nature, and as it bears a close resemblance to boron and carbon, it is better to class it along with these bodies, and to give it the name of silicon.