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A silicide is a compound that has silicon with (usually) more electropositive elements.


Silicon is more electropositive than carbon. Silicides are structurally closer to borides than to carbides.

Similar to borides and carbides, the composition of silicides cannot be easily specified as covalent molecules. The chemical bonds in silicides range from conductive metal-like structures to covalent or ionic. Silicides of all non-transition metals, with exception of beryllium, have been described.


Silicon atoms in silicides can have many possible organizations:

A silicide prepared by a self-aligned process is called a salicide. This is a process in which silicide contacts are formed only in those areas in which deposited metal (which after annealing becomes a metal component of the silicide) is in direct contact with silicon, hence, the process is self-aligned. It is commonly implemented in MOS/CMOS processes for ohmic contacts of the source, drain, and poly-Si gate..

Alkali and alkaline earth metals

Group 1 and 2 silicides e.g. Na2Si and Ca2Si react with water, yielding hydrogen and/or silanes. At Consumer Electronics Show (CES) 2012 a safe and eco-friendly 1kWh or 3kWh capacity mobile phone charger with sodium silicide that runs on water has introduced for 'people who spend time away from the electricity grid'. Any type of water can be used, including salt water and it can even run on puddle water providing it isn't thickened with mud or any other sediment. [1]

When magnesium silicide is placed into hydrochloric acid, HCl(aq), the gas silane, SiH4, is produced. This gas is the silicon analogue of methane, CH4, but is more reactive. Silane is pyrophoric, that is, due to the presence of oxygen, it spontaneously combusts in air:

Mg2Si(s) + 4HCl(aq) → SiH4(g) + 2MgCl2(s)
SiH4 + 2O2 → SiO2 + 2H2O

These reactions are typical of a Group 2 silicide. Mg2Si reacts similarly with sulfuric acid. Group 1 silicides are even more reactive. For example, sodium silicide, Na2Si, reacts rapidly with water to yield sodium silicate, Na2SiO3, and hydrogen gas. Rubidium silicide is pyrophoric, igniting in contact with air. [2]

Transition metals

The transition metal silicides are, in contrast, usually inert to aqueous solutions of everything with exception of hydrofluoric acid; however, they react with more aggressive agents, e.g. melted potassium hydroxide, or fluorine and chlorine when red-hot.

Other elements

Mercury, thallium, bismuth, and lead are immiscible with liquid silicon.


See also

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Silicon dioxide chemical compound

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Silane is an inorganic compound with chemical formula, SiH4, making it a group 14 hydride. It is a colourless, pyrophoric, toxic gas with a sharp, repulsive smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon.

Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colourless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications.

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In chemistry, neutralization or neutralisation is a chemical reaction in which an acid and a base react quantitatively with each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutralized solution depends on the acid strength of the reactants.

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Magnesium silicide chemical compound

Magnesium silicide, Mg2Si, is an inorganic compound consisting of magnesium and silicon. As-grown Mg2Si usually forms black crystals; they are semiconductors with n-type conductivity and have potential applications in thermoelectric generators.

Beryllium nitride chemical compound

Beryllium nitride, Be3N2, is a nitride of beryllium. It can be prepared from the elements at high temperature (1100–1500 °C), unlike Beryllium azide or BeN6, it decomposes in vacuum into beryllium and nitrogen. It is readily hydrolysed forming beryllium hydroxide and ammonia. It has two polymorphic forms cubic α-Be3N2 with a defect anti-fluorite structure, and hexagonal β-Be3N2. It reacts with silicon nitride, Si3N4 in a stream of ammonia at 1800–1900 °C to form BeSiN2.

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Disilane is a chemical compound with chemical formula Si2H6 that was identified in 1902 by Henri Moissan and Samuel Smiles (1877–1953). Moissan and Smiles reported disilane as being among the products formed by the action of dilute acids on metal silicides. Although these reactions had been previously investigated by Friedrich Woehler and Heinrich Buff between 1857 and 1858, Moissan and Smiles were the first to explicitly identify disilane. They referred to disilane as silicoethane. Higher members of the homologous series SinH2n+2 formed in these reactions were subsequently identified by Carl Somiesky (sometimes spelled "Karl Somieski") and Alfred Stock.

Methyltrichlorosilane chemical compound

Methyltrichlorosilane, also known as trichloromethylsilane, is an organosilicon compound with the formula CH3SiCl3. It is a colorless liquid with a sharp odor similar to that of hydrochloric acid. As methyltrichlorosilane is a reactive compound, it is mainly used a precursor for forming various cross-linked siloxane polymers.

Binary compounds of silicon any binary chemical compound containing just silicon and another chemical element

Binary compounds of silicon are binary chemical compounds containing silicon and one other chemical element. Technically the term silicide is reserved for any compounds containing silicon bonded to a more electropositive element. Binary silicon compounds can be grouped into several classes. Saltlike silicides are formed with the electropositive s-block metals. Covalent silicides and silicon compounds occur with hydrogen and the elements in groups 10 to 17.

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  1. "Mobile phone charger that runs on water invented for 'people who spend time away from the electricity grid'". January 12, 2012.
  2. Rubidium ampoule opened IN AIR for chemical reactions (Video). ChemicalForce. 22 Feb 2020. Event occurs at 10:51. Retrieved 2020-02-23.

Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.