Calcium peroxide
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| Identifiers | |
|---|---|
3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.013.764 
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| EC Number |
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| E number | E930 (glazing agents, ...) |
| 674257 | |
| KEGG | |
PubChem CID
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| RTECS number |
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| UNII | |
| UN number | 1457 |
CompTox Dashboard (EPA)
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| Properties | |
| CaO2 | |
| Molar mass | 72.0768 g/mol |
| Appearance | white or yellowish powder |
| Odor | odorless |
| Density | 2.91 g/cm3 |
| Melting point | ~ 355 °C (671 °F; 628 K) (decomposes) |
| decomposes | |
| Acidity (pKa) | 12.5 |
| -23.8·10−6 cm3/mol | |
Refractive index (nD)
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1.895 |
| Structure | |
| Orthorhombic[1] | |
| Pna21 | |
| 8[1] | |
| Hazards | |
| GHS pictograms |  
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| GHS Signal word | Warning |
GHS hazard statements
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H272, H315, H319, H335 |
| P210, P220, P221, P261, P264, P271, P280, P302+352, P304+340, P305+351+338, P312, P321, P332+313, P337+313, P362, P370+378, P403+233, P405, P501 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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>5000 mg/kg (oral, rat) >10000 mg/kg (dermal, rat) |
| Related compounds | |
Other anions
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Calcium oxide |
Other cations
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Strontium peroxide Barium peroxide Sodium peroxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
 (what is   ?)
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| Infobox references | |
Calcium peroxide or calcium dioxide is the inorganic compound with the formula CaO2. It is the peroxide (O22−) salt of Ca2+. Commercial samples can be yellowish, but the pure compound is white. It is almost insoluble in water.[2]
Structure and stability[]
As a solid, it is relatively stable against decomposition. In contact with water however it hydrolyzes with release of oxygen. Upon treatment with acid, it forms hydrogen peroxide.
Preparation[]
Calcium peroxide is produced by combining calcium salts and hydrogen peroxide:
- Ca(OH)2 + H2O2 → CaO2 + 2 H2O
The octahydrate precipitates upon the reaction of calcium hydroxide with dilute hydrogen peroxide. Upon heating it dehydrates.
Applications[]
It is mainly used as an oxidant to enhance the extraction of precious metals from their ores. In its second main application, it is used as a food additive under the E number E930 it is used as flour bleaching agent and improving agent.[2]
In agriculture it is used in the presowing treatments of . Also, calcium peroxide has found use in aquaculture to oxygenate and disinfect water. In the ecological restoration industry it is used in the treatment of soils. Calcium peroxide is used in a similar manner to magnesium peroxide for environmental restoration programs. It is used to restore soil and groundwater contaminated with petroleum by the process of enhanced in-situ bioremediation. It is a minor component of some dentifrices.
It is also used for curing polythioether polymers by oxidising terminal thiol groups to disulphide bridges.
References[]
- ^ Jump up to: a b Zhao, X.; Nguyen, M.C.; Wang, C.Z.; Ho, K.M. (2013). "Structures and stabilities of alkaline earth metal peroxides XO2 (X = Ca, Be, Mg) studied by a genetic algorithm". RSC Advances. 3 (44): 22135. doi:10.1039/C3RA43617A.
- ^ Jump up to: a b Harald Jakob, Stefan Leininger, Thomas Lehmann, Sylvia Jacobi, Sven Gutewort. "Peroxo Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_177.pub2.CS1 maint: multiple names: authors list (link)
- Peroxides
- Calcium compounds
- Food additives
- Bleaches
- Disinfectants
- Oxidizing agents