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| Names | |||
|---|---|---|---|
| Other names silicon tetraiodide Tetraiodosilane | |||
| Identifiers | |||
3D model (JSmol) | |||
| ChemSpider | |||
| ECHA InfoCard | 100.033.355  | ||
PubChem CID | |||
CompTox Dashboard (EPA) | |||
InChI
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SMILES
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| Properties | |||
Chemical formula | SiI4 | ||
| Molar mass | 535.7034 g/mol | ||
| Appearance | white powder | ||
| Density | 4.198 g/cm3 | ||
| Melting point | 120.5 °C (248.9 °F; 393.6 K) | ||
| Boiling point | 287.4 °C (549.3 °F; 560.5 K) | ||
| reacts | |||
| Solubility in organic solvents | soluble | ||
| Structure | |||
| tetrahedral | |||
| Hazards | |||
EU classification (DSD) (outdated) | not listed | ||
| R-phrases (outdated) | R61-R24/25-R34-R42/43 | ||
| S-phrases (outdated) | S53-S26-S36/37/39-S45 | ||
| NFPA 704 (fire diamond) | |||
| Flash point | −18 °C (0 °F; 255 K) | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
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Silicon tetraiodide is the chemical compound with the formula SiI4. It is a tetrahedral molecule with Si-I bond lengths of 2.432(5) Å.[1]
SiI4 is a precursor to silicon amides of the formula Si(NR2)4 (R = alkyl).[2] It has also been of interest in the manufacture and etching of silicon in microelectronics.
Reactions
This compound is stable among strong heating. It can be stored at room temperature for long periods but must be kept dry because it reacts quickly with water and moisture in the air. It can be made on a large scale by reaction of silicon or silicon carbide with iodine on heating to about 200 °C. Of more academic interest is the reaction of silane with iodine vapour at 130 - 150 °C, as this produces a series of compounds ranging from iodosilane SiH3I to diiodosilane SiH2I2 and triiodosilane SiHI3 as well. These compounds are colourless liquids at room temperature.[3] The last one can be readily distinguished from the similar carbon compound, iodoform which is a yellow solid at room temperature.
Comparison with other SiX4 compounds
| SiH4 | SiF4 | SiCl4 | SiBr4 | SiI4 | |
|---|---|---|---|---|---|
| b.p. (˚C)[4] | -111.9 | -90.3 | 56.8 | 155.0 | 290.0 |
| m.p. (˚C)[4] | -185 | -95.0 | -68.8 | 5.0 | 155.0 |
| Si-X bond length (Å) | >0.74 [5] | 1.55 | 2.02 | 2.20 | 2.43 |
| Si-X bond energy (kJ/mol)[6] | 384 | 582 | 391 | 310 | 234 |
References
- ^ Kolonits, Maria; Hargittai, Magdolna (1998). Structural Chemistry. 9 (5): 349–352. doi:10.1023/A:1022462926682. S2CID 96658381.
- ^ Banerjee, Chiranjib; Wade, Casey R.; Soulet, Axel; Jursich, Gregory; McAndrew, James; Belot, John A. (2006). "Direct syntheses and complete characterization of halide-free tetrakis(dialkylamino)silanes". Inorganic Chemistry Communications. 9 (7): 761. doi:10.1016/j.inoche.2006.04.027.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ a b Silicon Compounds, Silicon Halides. Collins, W.: Kirk-Othmer Encyclopedia of Chemical Technology; John Wiley & Sons, Inc, 2001.
- ^ https://www.answers.com/Q/What_is_the_bond_length_of_the_H-H_bond
- ^ Ebsworth, E. A. V. In Volatile Silicon Compounds; Taube, H.; Maddock, A. G.; Inorganic Chemistry; Pergamon Press Book: New York, NY, 1963; Vol. 4.