Barium oxide

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Barium oxide
Other names	Barium monoxide; barium protoxide; calcined baryta
Identifiers
CAS number	[1304-28-5]
Properties
Molecular formula	BaO
Molar mass	153.3 g/mol
Appearance	white solid
Density	5.7 g/cm³, solid
Melting point	1923 °C
Boiling point	~2000 °C
Solubility in water	3.8 g/100 ml (20 °C)
Structure
Crystal structure	cubic
Coordination geometry	Octahedral
Hazards
MSDS	External MSDS
EU classification	Harmful (Xn)
R-phrases	R20/22
S-phrases	(S2), S28
Flash point	non-flammable
Related compounds
Other anions	Barium hydroxide Barium peroxide
Other cations	Calcium oxide Strontium oxide
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Barium oxide, BaO, is a white hygroscopic compound formed by the burning of barium in oxygen, although it is often formed through the decomposition of other barium salts.^[1]

2Ba + O₂ → 2BaO

BaCO₃ → BaO + CO₂

It transforms into barium hydroxide on contact with water.

BaO + H₂O → Ba(OH)₂

1 Uses
2 Safety issues
3 References
4 External links

[edit] Uses

Barium oxide is used as a coating for hot cathodes, and in cathode ray tubes. It is used in the production of certain kinds of glass such as optical crown glass. It replaced lead oxide. Lead oxide was used to raise the refractive index, but it also raised the dispersive power. Barium oxide only raises the refractive index.^[2] Barium oxide also has use as an ethoxylation catalyst in the reaction of ethylene oxide and alcohols, which takes place 150 and 200°C.^[3]

[edit] Safety issues

Barium oxide is an irritant. If it contacts the skin or the eyes or is inhaled it causes pain and redness. However, it is more dangerous when ingested. It can cause nausea and diarrhea, muscle paralysis, cardiac arrhythmia, and can cause death. If ingested, medical attention should be sought immediately. Barium oxide also is dangerous to the environment. It is harmful especially to aquatic organisms^[4]