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)

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

Chemical compound

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.

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

References

^ Kolonits, Maria; Hargittai, Magdolna (1998). "Molecular Structure of Silicon Tetraiodide". 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.
^ P. W. Schenk (1963). "Silicon and Germanium". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2page=689. NY, NY: Academic Press.
^ 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.
^ "What is the bond length of the H-H bond?". Answers.com.
^ Ebsworth, E. A. V. In Volatile Silicon Compounds; Taube, H.; Maddock, A. G.; Inorganic Chemistry; Pergamon Press Book: New York, NY, 1963; Vol. 4.