Английская Википедия:Group 14 hydride
Шаблон:Short description Шаблон:Multiple image
Group 14 hydrides are chemical compounds composed of hydrogen atoms and group 14 atoms (the elements of group 14 are carbon, silicon, germanium, tin, lead and flerovium).
Tetrahydrides
The tetrahydride series has the chemical formula Шаблон:Chem2, 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.
| Compound | Chemical formula | Molecular geometry | Space-filling model |
|---|---|---|---|
| carbon tetrahydride hydrogen carbide methane (carbane) |
Шаблон:Chem2 | Файл:Methane-2D-dimensions.svg | Файл:Methane-3D-space-filling.svg |
| silicon tetrahydride hydrogen silicide (silane) |
Шаблон:Chem2 | Файл:Silane-2D.svg | Файл:Silane-3D-vdW.png |
| germanium tetrahydride hydrogen germanide (germane) |
Шаблон:Chem2 | Файл:Germane-2D-dimensions.png | Файл:Germane-3D-vdW.png |
| tin tetrahydride hydrogen stannide (stannane) |
Шаблон:Chem2 | Файл:Stannane-CRC-IR-Raman-dimensions-2D.png | Файл:Stannane-3D-vdW.png |
| lead tetrahydride hydrogen plumbide (plumbane) |
Шаблон:Chem2 | Файл:Plumban.svg | Файл:Plumbane-3D-vdW.png |
| flerovium tetrahydride hydrogen flerovide (flerovane) |
Шаблон:Chem2 |
Hexahydrides
This series has the chemical formula Шаблон:Chem2. Ethane is commonly found alongside methane in natural gas. The other hydrides of the chemical formula Шаблон:Chem2 are less stable than the corresponding tetrahydrides Шаблон:Chem2, and they are more and more less stable as X goes from carbon (ethane Шаблон:Chem2 is stable) down to lead (or flerovium) in the periodic table (diplumbane Шаблон:Chem2 is unknown[1]).
| Compound | Chemical formula | Molecular geometry | Space-filling model |
|---|---|---|---|
| Ethane (dicarbon hexahydride) (dicarbane) |
Шаблон:Chem2 | Файл:Ethane-staggered-CRC-MW-dimensions-2D.png | Файл:Ethane-3D-vdW.png |
| Disilane (disilicon hexahydride) |
Шаблон:Chem2 | Файл:Disilane.png | Файл:Disilane-3D-vdW.png |
| Digermane (digermanium hexahydride) |
Шаблон:Chem2 | Файл:Digermane molecule.png | Файл:Digermane-3D-vdW.png |
| Distannane (ditin hexahydride) |
Шаблон:Chem2 | Файл:Distannane.png | Файл:Distannane-3D-vdW.png |
| Diplumbane (dilead hexahydride) |
Шаблон:Chem2 | Файл:Diplumbane molecule.png | Файл:Diplumbane-3D-vdW.png |
| Diflerovane (diflerovium hexahydride) |
Шаблон:Chem2 |
Higher group 14 hydrides
All straight-chain saturated group 14 hydrides follow the formula Шаблон:Chem2, the same formula for the alkanes.
Many other group 14 hydrides are known. Carbon forms a huge variety of hydrocarbons (among the simplest alkanes are methane Шаблон:Chem2, ethane Шаблон:Chem2, propane Шаблон:Chem2, butane Шаблон:Chem2, pentane Шаблон:Chem2 and hexane Шаблон:Chem2, with a wide range of uses. There is also polyethylene Шаблон:Chem2, where n is very large, a stable hydrocarbon polymer, the most commonly produced plastic.[2] Hydrocarbons also include alkenes, which contain a double bond between carbon atoms (e.g. ethylene Шаблон:Chem2), alkynes, which contain a triple bond between carbon atoms (e.g. acetylene Шаблон:Chem2), cyclic and branched hydrocarbons (e.g. cyclohexane Шаблон:Chem2, limonene Шаблон:Chem2, which is a cyclic hydrocarbon with double bonds between carbon atoms, and neopentane Шаблон:Chem2, which is a branched hydrocarbon), as well as aromatic hydrocarbons such as benzene Шаблон:Chem2 and toluene Шаблон:Chem2), whose study forms the core of organic chemistry.[3]
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 Шаблон:Chem2, chloroform Шаблон:Chem2 and iodoform Шаблон:Chem2. Other such important chemicals include vinyl chloride Шаблон:Chem2, which is used in the production of PVC.
The other group 14 elements have a lower tendency to catenate. Hydrosilicons (binary silicon-hydrogen compounds), a silicon analogs of hydrocarbons, such as silanes Шаблон:Chem2 are known for n = 1–8, in which thermal stability decreasing as n increases (e.g. silane Шаблон:Chem2 and disilane Шаблон:Chem2), as are cyclosilanes (e.g. cyclopentasilane Шаблон:Chem2 and cyclohexasilane Шаблон:Chem2). They are very reactive, pyrophoric colourless gases or volatile liquids. Their volatility is intermediate between the alkanes and the germanes.[4] Unsaturated silanes, the silenes and silynes, have been characterized spectroscopically. The first members of each respectively are disilene Шаблон:Chem2 and disilyne Шаблон:Chem2, the silicon analogues of ethylene and acetylene respectively.
The first five hydrogermaniums Шаблон:Chem2 are known and are fairly similar to the hydrosilicones,[5] e.g. germane Шаблон:Chem2 and digermane Шаблон:Chem2. They are germanium analogues of alkanes.
Stannane Шаблон:Chem2, a strong reducing agent slowly decomposes at room temperature to tin and hydrogen gas, and is decomposed by concentrated aqueous acids or alkalis; distannane, Шаблон:Chem2 is still more unstable, and longer hydrostannums (hydrotins) are unknown. Stannane and distannane are tin analogues of methane and ethane respectively.
Plumbane Шаблон:Chem2 is very poorly characterised and is only known in trace amounts: even at low temperatures, synthesis methods that yield the other Шаблон:Chem2 compounds fail to give Шаблон:Chem2. No other hydroplumbums (hydroleads) are known.[1] However, some substituted diplumbanes, with a general chemical formula Шаблон:Chem2 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 Шаблон:Chem2 which contains carbon and lead. The other examples are methylsilane Шаблон:Chem2 which contains carbon and silicon, tris(trimethylsilyl)germanium hydride Шаблон:Chem2 which contain carbon, silicon and germanium, silylgermane or germylsilane Шаблон:Chem2 which contains silicon and germanium, and hexaphenyldiplumbane Шаблон:Chem2 which contains carbon and lead.[6]
See also
- Methylene Шаблон:Chem2
- Methylidyne Шаблон:Chem2
- Titanium(IV) hydride Шаблон:Chem2, a structural analog of the group 14 tetrahydrides
- Zirconium hydride Шаблон:Chem2, Шаблон:Chem2 and others
- Zirconium(II) hydride Шаблон:Chem2
- Uranium(IV) hydride Шаблон:Chem2
References
Bibliography
- ↑ 1,0 1,1 Greenwood and Earnshaw, p. 375.
- ↑ Whiteley, Kenneth S.; Heggs, T. Geoffrey; Koch, Hartmut; Mawer, Ralph L. and Immel, Wolfgang (2005) "Polyolefins" in Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH, Weinheim. Шаблон:Doi.
- ↑ Greenwood and Earnshaw, p. 301.
- ↑ Greenwood and Earnshaw, p. 337.
- ↑ Greenwood and Earnshaw, p. 374.
- ↑ Шаблон:Cite web
