Barium oxide

Cubic

Ba, O

Colorless powder

Fixed

5.72 g · cm -3

1918 ° C

2000 ° C

In water decomposition to barium

1.9841

Risk

0.5 mg · m -3 ( Ba)

-554 KJ · mol -1

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Barium oxide is the oxide of the alkaline earth metal is barium. It has the formula BaO.

Properties

Barium oxide is a colorless solid which melts at 1918 ° C. With water it reacts with vigorous evolution of heat to barium hydroxide.

It has a crystal structure of the sodium chloride type and reacts with moist air to the hydroxide with CO2 -containing air to form barium carbonate.

Representation

Technically, it is prepared by heating a carbon - barium carbonate mixture to about 1030 ° C in the laboratory by annealing of barium nitrate.

Use

Barium oxide is used as an absorbent for carbon dioxide, and as a drying agent as well as for the production of barium, barium hydroxide, organic barium, special glasses and oxide cathodes.

Barium oxide is subject to oxygen atmosphere an equilibrium reaction to Barium BaO2.

Between 500 and 600 ° C BaO reacts to barium. Above 600 ° C, the bound in the peroxide oxygen is discharged. BaO should therefore not be too hot. Since the equilibrium reaction is connected to the barium peroxide with heat (exothermic reaction) and volume change, the equilibrium shifts to the left with increasing temperature. One can therefore bind oxygen at low temperature and release at higher temperature.