Copper peroxide
Chemical compound - an oxide of copper with formula CuO2
From Wikipedia, the free encyclopedia
Copper peroxide is an inorganic compound with the chemical formula Cu(O2). The 1:2 ratio of copper and oxygen would be consistent with copper in its common +2 oxidation state and a peroxide group. Cu(O2) has attracted interest from a computational perspective. One highly cited analysis concludes that gaseous Cu(O2) is a superoxide, with copper in a +1 oxidation state: Cu+O−2.[1]
| Names | |
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| IUPAC name
Copper(II) peroxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
CompTox Dashboard (EPA) |
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| Properties | |
| Cu(O2) | |
| Molar mass | 95.945 g/mol |
| Appearance | Various |
| Related compounds | |
Related compounds |
Copper(IV) oxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Older literature claims that treatment of cold suspended Cu(OH)2 with H2O2 creates a brown hydrate of "copper dioxide," which rapidly decomposes in the presence of water to form ill-defined green and yellow salts above 0 °C.[2]
History
Species claimed to be "copper peroxide" have been claimed, e.g., by the reaction of cold solutions of Schweizer's reagent—a source of copper(II)—and hydrogen peroxide.[3] The Schweizer's reagent used must not contain excess ammonia.[3]
It was once claimed to result from the very slow reaction of finely divided cupric oxide with cold hydrogen peroxide.[4]
It has been claimed that brown "copper dioxide" synthesized from Cu(OH)2 can be dried above 100 °C without decomposition if the product is thoroughly rid of moisture via alcohol washings.[2] The resulting product is claimed to be a copper peroxide hydrate.
Several well-characterized molecular copper peroxide complexes have been reported, but these species always feature supporting organic ligands.[5]
Structure
Several substances claimed to be inorganic copper(II) peroxides have been reported,[6][7]: 22–23 with empirical formulae:
- Cu(O2)·H2O, a dark brown solid prepared by the reaction of freshly-made (blue) Cu(OH)2 with moderate-concentration solutions of H2O2 between −20 °C and 20 °C.[6][8][9] An alternative route is the reaction of an ethanol–water solution of CuCl2 with H2O2, followed by ethanolic KOH, at −40 to −50 °C.[6] Possible structures include Cu(OH)(OOH) (mixed hydroxide-hydroperoxide) and Cu(O2)·H2O (hydrate).[6] Electron spin resonance measurements indicate it does not contain CuO.[10] An early publication claims it turns olive-green with age, as well as upon reaction with excess peroxide.[11]
- Cu(O2)·H2O2·H2O, prepared by the reaction of freshly-made Cu(OH)2 with concentrated solutions of hydrogen peroxide between −36 °C and 20 °C.[6][8] A possible structure is the perhydrate Cu(OH)(OOH)·H2O2.[12]
- Cu2(O2)(OOH), an olive-green solid claimed to be obtainable at −79 °C.[6]