Titanium tetraiodide

Template:Chembox header | Titanium tetraiodide

Titanium tetraiodide
Template:Chembox header | General
Systematic name | Titanium(IV) iodide
Other names  | Titanium tetraiodide
Molecular formula | TiI4
SMILES | ?
Molar mass | 555.49 g/mol
Appearance  | red-brown crystals
CAS number | [7720-83-4]
Template:Chembox header | Properties
Density and phase | 4.3 g/cm3
Solubility in water | hydrolysis
Other solvents  | CH2Cl2
CHCl3
CS2
Melting point | 150 °C
Boiling point | 377°C
Template:Chembox header | Structure
Coordination
geometry | tetrahedral
Crystal structure | cubic (a = 12.21 Å)
Dipole moment | 0 D
Template:Chembox header | Hazards
MSDS | External MSDS
Main hazards | violent hydrolysis
corrosive
NFPA 704 |
R/S statement | R: 34-37
S: 26-36/37/39-45
RTECS number  | ?
Template:Chembox header | Supplementary data page
Structure and
properties | n, εr, etc.
Thermodynamic
data | Phase behaviour
Solid, liquid, gas
Spectral data | UV, IR, NMR, MS
Template:Chembox header | Related compounds
Related ? | ?
Related compounds  | titanium tetrachloride,
|titanium tetrabromide,
carbon tetraiodide,

Template:Chembox header | Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Titanium tetraiodide is TiI4. It is a rare molecular binary metal iodide, consisting of isolated molecules of tetrahedral Ti(IV) centers; the other example is Ta2I10. Reflecting its molecular character, TiI4 can be distilled without decomposition at one atmosphere. The compound is a close relative to TiCl4. The difference in melting point between TiCl4 (m.p. -24 °C) and TiI4 (m.p. 150 °C) is comparable to the difference between the melting points of CCl4 (m.p. -23 °C) and CI4 (m.p. 168 °C), reflecting the stronger intermolecular van der Waals bonding in the iodides.

## Contents

* 1 Production
* 2 Reactions
* 3 References
* 4 External links

## Production

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Three methods are well known: 1) From the elements, typically using a tube furnace at 425 °C:

Ti + 2 I2 → TiI4

This reaction can be reversed to produce highly pure films of Ti metal.

2) Exchange reaction from titanium tetrachloride and HI.

TiCl4 \+ 4 HI → TiI4 \+ 4 HCl

3) Oxide-iodide exchange from aluminium iodide.

3 TiO2 \+ 4 AlI3 → 3 TiI4 \+ 2 Al2O3

## Reactions

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Like TiCl4 and TiBr4 , TiI4 forms adducts with Lewis bases, and it can also be reduced. When the reduction is conducted in the presence of Ti metal, one obtains polymeric Ti(III) and Ti(II) derivatives such as CsTi2I7 and the chain CsTiI3, respectively. As a solution in CH2Cl2, TiI4 exhibits some reactivity toward alkenes and alkynes resulting in organoiodine derivatives.

## References

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* Blumenthal WB, Smith H (1950). "Titanium tetraiodide, Preparation and Refining". Industrial and Engenieering Chemistry. 2: 249. DOI
* Tornqvist EGM, Libby WF (1979). "Crystal Structure, Solubility, and Electronic Spectrum of Titanium Tetraiodide". Inorganic Chemistry. 18: 1792. DOI
* Lowery, R. N.; Fay, R. C. "Titanium(IV) Iodide" Inorganic Syntheses 1967, volume X, pages 1-6.
* Shimizu, Makoto; Toyoda, Tadahiro; Baba, Toru. An Intriguing Hydroiodination of Alkenes and Alkynes with Titanium Tetraiodide. Synlett 2005, volume 16, pages 2516-2518.
* Jongen, L.; Gloger, T.; Beekhuizen, J.; Meyer, G. "Divalent Titanium: The Halides ATiX3 (A = K, Rb, Cs; X = Cl, Br, I)" Zeitschrift fur Anorganische und Allgemeine Chemie 2005, volume 631, pages 582-586.

## External links

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