1304-39-8

Crystalline powder. Decomposes in water.

In photocells, semiconductors.

Barium selenide has the molecular formula of BaSe and the molecular weight of 216.2956 g/mol. Its CAS number is 1304-39-8. It is a white crystalline powder having a melting point of 1782°C. Its density is 5.02 g/cm³. It reacts with water so that an aqueous method of precipitation cannot be used to prepare this compound. Barium selenide is very moisture sensitive, and must be handled under inert conditions. It can be prepared by reaction of the oxide or carbonate with Se, or by the reduction of the selenate with hydrogen gas:
2BaCO3+ 5Se+ Heat ? 2BaSe+ 3SeO2+ CO2
BaSeO4+ 4H2 ? BaSe+ 4H2O
Strontium selenide and barium selenide both have a simple cubic structure, with cube edges equal to 3.117? and 3.308 ? , respectively.

BaSeO4 + 4 H2 = BaSe + 4 H2O
The selenate (about 1 g.) is distributed in a thin layer over a quartz boat 10 cm. long and 1 cm. wide. The drying at 200°C is repeated, this time in a reaction tube and in a stream of N2. Reduction in a stream of H2 follows. It should continue for two hours at 500°C for BaSeO4.