Silicon tetraiodide
{{chembox
| Verifiedfields = changed
| verifiedrevid = 464390537
| ImageFile = Tetraiodsilan Natta.svg
| ImageSize = 150px
| ImageFileL2 = Silicon-tetraiodide-3D-balls.png
| ImageFileR2 = Silicon-tetraiodide-3D-vdW.png
| ImageFile3 = Йодид кремния.jpg
| IUPACName =
| OtherNames = silicon tetraiodide
Tetraiodosilane
| Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite|changed|??}}
| CASNo = 13465-84-4
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 75335
| InChI = 1/I4Si/c1-5(2,3)4
| InChIKey = CFTHARXEQHJSEH-UHFFFAOYAL
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/I4Si/c1-5(2,3)4
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = CFTHARXEQHJSEH-UHFFFAOYSA-N
| EC_number = 236-706-2
| PubChem = 83498
| SMILES = I[Si](I)(I)I
}}
| Section2 = {{Chembox Properties
| Formula = SiI4
| MolarMass = 535.7034 g/mol
| Appearance = white powder
| Density = 4.198 g/cm3
| MeltingPtC = 120.5
| BoilingPtC = 287.4
| Solubility = reacts
| SolubleOther = soluble
| Solvent = organic solvents
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| Section3 = {{Chembox Structure
| MolShape = tetrahedral
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| Section8 = {{Chembox Hazards
| GHSPictograms = {{GHS05}}{{GHS06}}{{GHS07}}{{GHS08}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|301|311|314|317|334|360}}
| PPhrases = {{P-phrases|201|202|260|261|264|270|272|280|281|285|301+310|301+330+331|302+352|303+361+353|304+340|304+341|305+351+338|308+313|310|312|321|322|330|333+313|342+311|361|363|405|501}}
| MainHazards =
| NFPA-H = 2
| NFPA-R = 0
| NFPA-F = 0
}}
{{Chembox Related
| OtherAnions = Silicon tetrafluoride
Silicon tetrachloride
Silicon tetrabromide
| OtherCations = Carbon tetraiodide
Germanium tetraiodide
Tin(IV) iodide
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| OtherFunction_label =
| OtherCompounds =
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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.{{cite journal|doi=10.1023/A:1022462926682|year=1998|last1=Kolonits|first1=Maria|last2=Hargittai|first2=Magdolna|title=Molecular Structure of Silicon Tetraiodide|journal=Structural Chemistry|volume=9|issue=5|pages=349–352|s2cid=96658381}}
SiI4 is a precursor to silicon amides of the formula Si(NR2)4 (R = alkyl).{{cite journal|doi=10.1016/j.inoche.2006.04.027|title=Direct syntheses and complete characterization of halide-free tetrakis(dialkylamino)silanes|year=2006|last1=Banerjee|first1=Chiranjib|last2=Wade|first2=Casey R.|last3=Soulet|first3=Axel|last4=Jursich|first4=Gregory|last5=McAndrew|first5=James|last6=Belot|first6=John A.|journal=Inorganic Chemistry Communications|volume=9|issue=7|pages=761}} 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:{{cite book|author1=P. W. Schenk|chapter=Silicon and Germanium|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=NY, NY|volume=2page=689}}
:{{chem2|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.{{Greenwood&Earnshaw}} The last one can be readily distinguished from the similar carbon compound, iodoform which is a yellow solid at room temperature.
Comparison with other SiX<sub>4</sub> compounds
| class="wikitable" style="text-align:center"; border="5"
! !! SiH4 !! SiF4 !! SiCl4 !! SiBr4 !! SiI4 | |||||
| b.p. (˚C)Silicon Compounds, Silicon Halides. Collins, W.: Kirk-Othmer Encyclopedia of Chemical Technology; John Wiley & Sons, Inc, 2001. | −111.9 | −90.3 | 56.8 | 155.0 | 290.0 |
| m.p. (˚C) | −185 | −95.0 | −68.8 | 5.0 | 155.0 |
| Si-X bond length (Å) | >0.74 {{Cite web|url=https://www.answers.com/Q/What_is_the_bond_length_of_the_H-H_bond|title = What is the bond length of the H-H bond?| website=Answers.com }} | 1.55 | 2.02 | 2.20 | 2.43 |
| Si-X bond energy (kJ/mol)Ebsworth, E. A. V. In Volatile Silicon Compounds; Taube, H.; Maddock, A. G.; Inorganic Chemistry; Pergamon Press Book: New York, NY, 1963; Vol. 4. | 384 | 582 | 391 | 310 | 234 |
References
External links
- [http://www.webelements.com/compounds/silicon/silicon_tetraiodide.html webelements page]
{{silicon compounds}}
{{Silicides}}
{{Iodides}}
Category:Inorganic silicon compounds
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