Barium oxide

Barium oxide, BaO, is a white hygroscopic non-flammable compound. It has a cubic structure and is used in cathode ray tubes, crown glass, and catalysts. It is harmful to human skin and if swallowed in large quantity causes irritation. Excessive quantities of barium oxide may lead to death.

It is prepared by heating barium carbonate with coke, carbon black or tar or by thermal decomposition of Barium nitrate.

Uses

Barium oxide is used as a coating for hot cathodes, for example, those in cathode ray tubes. It replaced lead(II) oxide in the production of certain kinds of glass such as optical crown glass. While lead oxide raised the refractive index, it also raised the dispersive power, which barium oxide does not alter. Barium oxide also has use as an ethoxylation catalyst in the reaction of ethylene oxide and alcohols, which takes place between 150 and 200°C.

It is also a source of pure oxygen through heat fluctuation. It readily oxidises to BaO_1+x by formation of a peroxide ion. The complete peroxidation of BaO to BaO₂ occurs at moderate temperatures but the increased entropy of the O₂ molecule at high temperatures means that BaO₂ decomposes to O₂ and BaO at 1175K.

Barium oxide (data page)

This page provides supplementary chemical data on barium oxide.

Material Safety Data Sheet

Structure and properties

Thermodynamic properties

Spectral data

References

Except where noted otherwise, data relate to standard ambient temperature and pressure.

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