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
Silicon tetraiodide.PNG
Other names
silicon tetraiodide
  • 13465-84-4 ☒N
3D model (JSmol)
  • Interactive image
  • 75335 checkY
ECHA InfoCard 100.033.355 Edit this at Wikidata
EC Number
  • 236-706-2
  • 83498
  • DTXSID5065489 Edit this at Wikidata
  • InChI=1S/I4Si/c1-5(2,3)4 checkY
  • InChI=1/I4Si/c1-5(2,3)4
  • I[Si](I)(I)I
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 organic solvents soluble
GHS labelling:
GHS05: CorrosiveGHS06: ToxicGHS07: Exclamation markGHS08: Health hazard
H301, H311, H314, H317, H334, H360
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).
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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.


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 compoundsEdit

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


  1. ^ Kolonits, Maria; Hargittai, Magdolna (1998). Structural Chemistry. 9 (5): 349–352. doi:10.1023/A:1022462926682. S2CID 96658381. {{cite journal}}: Missing or empty |title= (help)
  2. ^ 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.
  3. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  4. ^ a b Silicon Compounds, Silicon Halides. Collins, W.: Kirk-Othmer Encyclopedia of Chemical Technology; John Wiley & Sons, Inc, 2001.
  5. ^ "What is the bond length of the H-H bond?".
  6. ^ Ebsworth, E. A. V. In Volatile Silicon Compounds; Taube, H.; Maddock, A. G.; Inorganic Chemistry; Pergamon Press Book: New York, NY, 1963; Vol. 4.

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