Silicon tetraiodide

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]

Silicon tetraiodide

Names
Other names silicon tetraiodide Tetraiodosilane
Identifiers
CAS Number	13465-84-4 N
3D model (JSmol)	Interactive image
ChemSpider	75335 Y
ECHA InfoCard	100.033.355
EC Number	236-706-2
PubChem CID	83498
CompTox Dashboard (EPA)	DTXSID5065489
InChI InChI=1S/I4Si/c1-5(2,3)4 Y Key: CFTHARXEQHJSEH-UHFFFAOYSA-N Y InChI=1/I4Si/c1-5(2,3)4 Key: CFTHARXEQHJSEH-UHFFFAOYAL
SMILES I[Si](I)(I)I
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)
Solubility in water	reacts
Solubility in organic solvents	soluble
Structure
Molecular shape	tetrahedral
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H311, H314, H317, H334, H360
Precautionary statements	P201, P202, P260, P261, P264, P270, P272, P280, P281, P285, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P304+P341, P305+P351+P338, P308+P313, P310, P312, P321, P322, P330, P333+P313, P342+P311, P361, P363, P405, P501
NFPA 704 (fire diamond)	2 0 0
Related compounds
Other anions	Silicon tetrafluoride Silicon tetrachloride Silicon tetrabromide
Other cations	Carbon tetraiodide Germanium tetraiodide Tin(IV) iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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.

Synthesis and reactions

This compound is produced by treating silicon-copper mixture with iodine:^[3]

Si + I₂ → SiI₄

It reacts quickly with water and moisture in the air.

It can also 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.^[4] 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)[5]	−111.9	−90.3	56.8	155.0	290.0
m.p. (˚C)[5]	−185	−95.0	−68.8	5.0	155.0
Si-X bond length (Å)	>0.74 [6]	1.55	2.02	2.20	2.43
Si-X bond energy (kJ/mol)[7]	384	582	391	310	234