Barium peroxide
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| Names | |
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| IUPAC name
barium peroxide
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| Other names
Barium binoxide,
Barium dioxide | |
| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.013.754 |
| EC Number |
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PubChem CID
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| RTECS number |
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CompTox Dashboard (EPA)
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| Properties | |
| BaO2 | |
| Molar mass | 169.33 g/mol (anhydrous) 313.45 (octahydrate) |
| Appearance | Grey-white crystalline (anhydrous) colorless solid (octahydrate) |
| Odor | odorless |
| Density | 5.68 g/cm3 (anhydrous) 2.292 g/cm3 (octahydrate) |
| Melting point | 450 °C (842 °F; 723 K) |
| Boiling point | 800 °C (1,470 °F; 1,070 K) |
| anhydrous 0.091 g/100 mL (20 °C) octahydrate 0.168 g/cm3 | |
| Solubility | soluble in dilute acid insoluble in alcohol, ether, acetone |
| Structure | |
| Tetragonal [2] | |
| D174h, I4/mmm, tI6 | |
| 6 | |
| Hazards | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Barium peroxide is the chemical compound with the formula BaO2. This grey-white solid is one of the most common inorganic peroxides. Barium peroxide is an oxidizing agent, which is used for bleaching. It is used in fireworks as an oxidizer,[3] which also gives a vivid green colour, as do all barium compounds.
Chemistry
Barium peroxide is a peroxide, containing O2−
2 subunits wherein the oxygen atoms bond to each other as well as to the barium. The solid adopts the same structure as calcium carbide, CaC2.
Preparation
Barium peroxide arises by the reversible absorption of O2 by barium oxide. The oxygen is released above 1100 K.[4]
- 2 BaO + O2 ⇌ 2 BaO2
This reaction is the basis for the now-obsolete Brin process for separating oxygen from the atmosphere. It is driven by differences in the vibrational entropy of the O2 molecule in comparison to the solid phases in the reversible reaction.[5] Other oxides, e.g. Na2O and SrO, behave similarly.[6]
Hydrogen peroxide can also be prepared via the related reaction:
- BaO2 + H2SO4 → H2O2 + BaSO4
The insoluble barium sulfate is filtered from the mixture.
Alternatively, barium peroxide can also be prepared by the oxidation of barium oxide with air at 537 °C.
Footnotes
- ^ Accommodation of Excess Oxygen in Group II Monoxides - S.C. Middleburgh, R.W. Grimes and K.P.D. Lagerlof http://onlinelibrary.wiley.com/doi/10.1111/j.1551-2916.2012.05452.x/abstract.
- ^ Massalimov, I. A.; Kireeva, M. S.; Sangalov, Yu. A. (2002). Inorganic Materials. 38 (4): 363. doi:10.1023/A:1015105922260.
{{cite journal}}: Missing or empty|title=(help) - ^ "Data Sheet". Data Sheet. Hummel Croton Inc. Archived from the original on 26 February 2007. Retrieved 2007-02-01.
{{cite web}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help) - ^ Accommodation of Excess Oxygen in Group II Monoxides - S.C. Middleburgh, R.W. Grimes and K.P.D. Lagerlof http://onlinelibrary.wiley.com/doi/10.1111/j.1551-2916.2012.05452.x/abstract.
- ^ Accommodation of Excess Oxygen in Group II Monoxides - S.C. Middleburgh, R.W. Grimes and K.P.D. Lagerlof http://onlinelibrary.wiley.com/doi/10.1111/j.1551-2916.2012.05452.x/abstract.
- ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.