Titanium(III) iodide
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| ImageFile = TiI3side-onview.jpg
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| IUPACName = Titanium(III) iodide
| OtherNames = Titanium triiodide
|Section1={{Chembox Identifiers
| CASNo = 13783-08-9
| CASNo_Ref = {{Cascite|correct|CAS}}
| PubChem = 18955717
| SMILES = I[Ti](I)I
| StdInChI=1S/3HI.Ti/h3*1H;/q;;;+3/p-3
| StdInChIKey = HUYLAMJIPCOVOM-UHFFFAOYSA-K
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|Section2={{Chembox Properties
| I=3|Ti=1
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| Appearance = black-violet solid
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|Section3={{Chembox Hazards
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|Section8={{Chembox Related
| OtherAnions = Titanium(III) fluoride
Titanium(III) bromide
Titanium(III) chloride
| OtherCations = Zirconium(III) iodide
Hafnium(III) iodide
| OtherCompounds = Titanium(IV) iodide
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Titanium(III) iodide is an inorganic compound with the formula TiI3. It is a dark violet solid that is insoluble in solvents, except upon decomposition.
Preparation and structure
Titanium(III) iodide can be prepared by reaction of titanium with iodine:F. Hein, S. Herzog "Molybdenum(III) Bromide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1407.
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It can also be obtained by reduction of TiI4, e.g., with aluminium.{{citation|surname1=Catherine E. Housecroft, A. G. Sharpe|title=Inorganic Chemistry|publisher=Pearson Education|pages=601|isbn=0-13-039913-2|year=2005|language=German|url=https://books.google.com/books?id=_1gFM51qpAMC}}
In terms of its structure, the compound exists as a polymer of face-sharing octahedra. Above 323 K, the Ti---Ti spacing are equal, but below that temperature, the material undergoes a phase transition. In the low temperature phase, the Ti---Ti contacts are alternating short and long. The low temperature structure is similar to that of molybdenum tribromide.{{cite journal|first1=Joachim|last1=Angelkort|first2=Andreas|last2=Schoenleber|first3=Sander|last3=van Smaalen|title=Low- and High-Temperature Crystal Structures of TiI3|journal=Journal of Solid State Chemistry|volume=182|year=2009|issue=3 |page=525–53|doi=10.1016/j.jssc.2008.11.028|bibcode=2009JSSCh.182..525A }}.