Selenium trioxide

Selenium trioxide[1]
Identifiers
CAS number	13768-86-0
PubChem	115128
ChemSpider	103019 Y
Jmol-3D images	Image 1
SMILES O=[SeH2](=O)=O
InChI InChI=1S/O3Se/c1-4(2)3 Y Key: VFLXBUJKRRJAKY-UHFFFAOYSA-N Y InChI=1/O3Se/c1-4(2)3 Key: VFLXBUJKRRJAKY-UHFFFAOYAC
Properties
Molecular formula	SeO3
Molar mass	126.96 g/mol
Appearance	white hygroscopic crystals
Density	3.44 g/cm3
Melting point	118.35 °C
Boiling point	sublimes
Solubility in water	very soluble
Structure
Crystal structure	tetragonal
Hazards
EU classification	not listed
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 trioxide (SeO₃) is a chemical compound used in the manufacture of photoelectric cells and solar energy devices. A laboratory preparation is to react anhydrous K₂SeO₄ and SO₃. The compound is thermodynamically unstable with respect to selenium dioxide. The solid consists of cyclic tetramers, Se₄O₁₂. In the gas phase there is some dissociation into the monomer.
It is a strong oxidizing agent, as is selenic acid and all selenates.

Structure

The molecular shape of selenium trioxide is triagonal planar. Selenium trioxide is a nonpolar molecule. the bonds between the selenium and the oxygen are double bonds. The bond angles are all 120°, and the molecule is flat. There are no lone bonding pairs.

References

1. ^ Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–81. ISBN 0-8493-0594-2 

• Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
• Schmidt, Prof. Dr. Max; Dr. P. Bornmann, Dr. Irmgard Wilhelm (1963-10-02). "The Chemistry of Selenium Trioxide". Angewandte Chemie International Edition in English 2 (11): 691–692. doi:10.1002/anie.196306913.