Selenium tetrachloride

Selenium tetrachloride
IUPAC name

Selenium tetrachloride
Identifiers
CAS number 10026-03-6 Y
PubChem 66205
ChemSpider 59590 Y
RTECS number VS7875000
Jmol-3D images Image 1
Properties
Molecular formula SeCl4
Molar mass 220.771 g/mol
Appearance white to yellow crystals
Density 2.6 g/cm³, solid
Melting point

sublimes at 191.4°C[1]
Solubility in water decomposes in water
Structure
Crystal structure Monoclinic, mS80
Space group C12/c1, No. 15
Molecular shape Seesaw (gas phase)
Hazards
EU classification Toxic (T), Dangerous for the environment (N)
R-phrases R23/25, R33, R50/53
S-phrases S20/21, S28, S45, S60, S61[2]
NFPA 704
0
3
0
Flash point non-flammable
Related compounds
Other anions Selenium tetrafluoride
Selenium tetrabromide
Selenium dioxide
Other cations Dichlorine monoxide
Sulfur tetrachloride
Tellurium tetrachloride
 Y (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Selenium tetrachloride is the inorganic compound composed with the formula SeCl4. This compound exists as yellow to white volatile solid. It is one of two commonly available selenium chlorides, the other example being selenium monochloride, Se2Cl2. SeCl4 is used in the synthesis of other selenium compounds.

Synthesis and structure

The compound is prepared by treating selenium with chlorine:[3] When the reacting selenium is heated, the product sublimes from the reaction flask. The volatility of selenium tetrachloride can be exploited to purification of selenium.

Solid SeCl4 consists of separated Cl− and [SeCl3]+ centers. The cations are pyramidal consistent with the predictions of VSEPR theory. Gaseous SeCl4 contains SeCl2 and chlorine, which recombine upon condensation.

Reactions

Selenium tetrachloride can be reduced in situ to the dichloride using triphenylstibine:

SeCl4 + SbPh3 → SeCl2 + Cl2SbPh3

Selenium tetrachloride reacts with water to give selenous and hydrochloric acids:[4]

SeCl4 + 3 H2O → H2SeO3 + 4 HCl

Upon treatment with selenium dioxide, it gives selenium oxychloride:[4]

SeCl4 + SeO2 → 2SeOCl2

References

  1. ^ Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 487. ISBN 0849305942. http://books.google.com/?id=lFjg0L-uOxoC&pg=PT872. Retrieved 2008-07-02 
  2. ^ "323527 Selenium tetrachloride". Sigma-Aldrich. http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/323527/. Retrieved 2008-07-02. 
  3. ^ Henry G. Nowak, John F. Suttle “Selenium (IV) Chloride” Inorganic Syntheses, 1957, Volume 5, 125-127. doi:0.1002/9780470132364.ch33.
  4. ^ a b Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.