Aluminium selenide

Aluminium selenide^[1]

Names
Other names Aluminium(III) selenide
Identifiers
CAS Number	1302-82-5
ChemSpider	144477
EC Number	215-110-6
Jmol interactive 3D	Image
PubChem	164804
InChI InChI=1S/2Al.3Se/q2*+3;3*-2 Key: CYRGZAAAWQRSMF-UHFFFAOYSA-N InChI=1/2Al.3Se/q2*+3;3*-2 Key: CYRGZAAAWQRSMF-UHFFFAOYAJ
SMILES [Al+3].[Al+3].[Se-2].[Se-2].[Se-2]
Properties
Chemical formula	Al2Se3
Molar mass	290.84 g/mol
Appearance	yellow to brown powder
Odor	odorless
Density	3.437 g/cm^3
Melting point	947 °C (1,737 °F; 1,220 K)
Solubility in water	decomposes
Structure
Crystal structure	Monoclinic, mS20, Space group Cc, No. 9[2]
Thermochemistry
Std molar entropy (S^o298)	154.8 J/mol K
Std enthalpy of formation (ΔfH^o298)	-566.9 kJ/mol
Hazards
EU classification (DSD)	not listed
NFPA 704	0 3 3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Aluminium selenide is the inorganic compound with the formula Al₂Se₃.

Preparation

It is a solid prepared by igniting a mixture of the elements at 1,000 °C (1,830 °F):

2 Al + 3 Se → Al₂Se₃

The pure compound is white, but typical samples are coloured.^[3] Samples of aluminium selenide must be protected from moisture, because the compound hydrolyzes readily, giving off highly toxic hydrogen selenide gas:^[4]

Al₂Se₃ + 3 H₂O → Al₂O₃ + 3 H₂Se

Uses

Al₂Se₃ has been used as a precursor to hydrogen selenide, which is released when the solid is treated with acids.^[3]

Safety

Aluminium selenide should be stored and handled away from moisture and air.

References

1. Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–40. ISBN 0-8493-0594-2
2. Steigmann, G. A.; Goodyear, J. (1966). "The crystal structure of Al2Se3". Acta Crystallographica 20: 617. doi:10.1107/S0365110X66001506.
3. Waitkins, G. R.; Shutt, R. (1946). "Aluminum Selenide and Hydrogen Selenide". Inorganic Syntheses 2: 183–186. doi:10.1002/9780470132333.ch55.
4. Bernd E. Langner "Selenium and Selenium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a23_525.