Barium oxide
<templatestyles src="Module:Hatnote/styles.css"></templatestyles>
200px | |
Names | |
---|---|
Other names
Barium monoxide
Barium protoxide Calcined baryta Baria |
|
Identifiers | |
1304-28-5 | |
ChemSpider | 56180 |
Jmol 3D model | Interactive image |
PubChem | 62392 |
RTECS number | CQ9800000 |
|
|
|
|
Properties | |
BaO | |
Molar mass | 153.326 g/mol |
Appearance | white solid |
Density | 5.72 g/cm3, solid |
Melting point | 1,923 °C (3,493 °F; 2,196 K) |
Boiling point | ~ 2,000 °C (3,630 °F; 2,270 K) |
3.48 g/100 mL (20 °C) 90.8 g/100 mL (100 °C) Reacts to form Ba(OH)2 |
|
Solubility | soluble in ethanol, dilute mineral acids and alkalies; insoluble in acetone and liquid ammonia |
Structure | |
cubic, cF8 | |
Fm3m, No. 225 | |
Octahedral | |
Thermochemistry | |
Std molar
entropy (S |
70 J·mol−1·K−1[1] |
Std enthalpy of
formation (ΔfH |
−582 kJ·mol−1[2] |
Vapor pressure | {{{value}}} |
Related compounds | |
Other anions
|
Barium hydroxide Barium peroxide |
Other cations
|
Calcium oxide Strontium oxide |
Supplementary data page | |
Refractive index (n), Dielectric constant (εr), etc. |
|
Thermodynamic
data |
Phase behaviour solid–liquid–gas |
UV, IR, NMR, MS | |
verify (what is ?) | |
Infobox references | |
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.[citation needed]
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.[3] 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.[4]
It is also a source of pure oxygen through heat fluctuation. It readily oxidises to BaO1+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.[5]
Preparation
Barium oxide is made by heating barium carbonate with coke, carbon black or tar. It may also be prepared by thermal decomposition of barium nitrate.[6] Likewise, it is often formed through the decomposition of other barium salts.[7]
- 2Ba + O2 → 2BaO
- BaCO3 → BaO + CO2
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 should not be released environmentally; it is harmful to aquatic organisms.[8]
See Also
References
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ S.C. Middleburgh, K.P.D. Lagerlof, R.W. Grimes - Accommodation of Excess Oxygen in Group II Oxides http://onlinelibrary.wiley.com/doi/10.1111/j.1551-2916.2012.05452.x/pdf
- ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
External links
- Pages with broken file links
- Articles without EBI source
- Articles without KEGG source
- Articles without UNII source
- Pages using collapsible list with both background and text-align in titlestyle
- Chemical articles having calculated molecular weight overwritten
- Chemical articles having a data page
- Articles with unsourced statements from September 2014
- Barium compounds
- Oxides