Group 14 hydride


Group 14 hydrides are chemical compounds composed of hydrogen atoms and group 14 atoms.

Tetrahydrides

The tetrahydride series has the chemical formula, with X representing any of the carbon family. Methane is commonly the result of the decomposition of organic matter and is a greenhouse gas. The other hydrides are generally unstable, poisonous metal hydrides.
They take on a pyramidal structure, and as such are not polar molecules like the other p-block hydrides.
Unlike other light hydrides such as ammonia, water and hydrogen fluoride, methane does not exhibit any anomalous effects attributed to hydrogen bonding, and so its properties conform well to the prevailing trend of heavier group 14 hydrides.
CompoundChemical formulaMolecular geometrySpace-filling model
carbon tetrahydride
hydrogen carbide
methane
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silicon tetrahydride
hydrogen silicide
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germanium tetrahydride
hydrogen germanide
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tin tetrahydride
hydrogen stannide
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lead tetrahydride
hydrogen plumbide
flerovium tetrahydride
hydrogen flerovide

Hexahydrides

This series has the chemical formula. Ethane is commonly found alongside methane in natural gas. The other hydrides of the chemical formula are less stable than the corresponding tetrahydrides, and they are more and more less stable as X goes from carbon down to lead in the periodic table.
CompoundChemical formulaMolecular geometrySpace-filling model
Ethane
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Disilane
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Digermane
Distannane
Diplumbane
Diflerovane

Higher group 14 hydrides

All straight-chain saturated group 14 hydrides follow the formula, the same formula for the alkanes.
File:Cubane-3D-vdW.png|thumb|right|100px|Cubane, a Platonic hydrocarbon and prismane
Many other group 14 hydrides are known. Carbon forms a huge variety of hydrocarbons, alkynes, which contain a triple bond between carbon atoms, cyclic and branched hydrocarbons, whose study forms the core of organic chemistry.
Alongside hydrogen, carbon can form compounds with the chemically similar halogens, forming haloalkanes. The simplest of this series, the halomethanes, contain compounds such as dichloromethane, chloroform and iodoform. Other such important chemicals include vinyl chloride, which is used in the production of PVC.
The other group 14 elements have a lower tendency to catenate. Hydrosilicons, a silicon analogs of hydrocarbons, such as silanes are known for n = 1–8, in which thermal stability decreasing as n increases, as are cyclosilanes. They are very reactive, pyrophoric colourless gases or volatile liquids. Their volatility is intermediate between the alkanes and the germanes. Unsaturated silanes, the silenes and silynes, have been characterized spectroscopically. The first members of each respectively are disilene and disilyne, the silicon analogues of ethylene and acetylene respectively.
The first five hydrogermaniums are known and are fairly similar to the hydrosilicones, e.g. germane and digermane. They are germanium analogues of alkanes.
Stannane, a strong reducing agent slowly decomposes at room temperature to tin and hydrogen gas, and is decomposed by concentrated aqueous acids or alkalis; distannane, is still more unstable, and longer hydrostannums are unknown. Stannane and distannane are tin analogues of methane and ethane respectively.
Plumbane is very poorly characterised and is only known in trace amounts: even at low temperatures, synthesis methods that yield the other compounds fail to give. No other hydroplumbums are known. However, some substituted diplumbanes, with a general chemical formula are more stable, where the R groups are organyl.
Compounds containing hydrogen and multiple group 14 elements are known, one of the most famous of these being tetraethyllead which contains carbon and lead. The other examples are methylsilane which contains carbon and silicon, tris(trimethylsilyl)germanium hydride which contain carbon, silicon and germanium, silylgermane or germylsilane which contains silicon and germanium, and hexaphenyldiplumbane which contains carbon and lead.