Chromium(VI) oxide peroxide

Preparation and properties

Chromium(VI) oxide peroxide is formed by the addition of acidified hydrogen peroxide solutions to solutions of metal chromates or dichromates, such as sodium chromate or potassium dichromate. The generally yellow chromates or orange dichromates turn to dark blue as "chromium(VI) oxide peroxide" forms: :

The structure of the pyridine complex has been determined crystallographically. Adducts with other N-heterocycles have also been characterized similarly.

Aqueous chromium(VI) oxide peroxide decomposes in a few seconds, turning green as chromium(III) compounds are formed. :

Stable adducts of the type include those with L = diethyl ether, 1-butanol, ethyl acetate, or amyl acetate. They form by adding a layer of the organic solvent above the chromate/dichromate solution and shaking during the addition of hydrogen peroxide.

The etherate, bis(pyridine) and pyridine complexes of this compound have been found to be effective oxidants in organic chemistry.

is sometimes said to have a "butterfly-like" structure due to its arrangement according to valence bond theory.

Gallery

File:Solution of CrO5.jpg|An aqueous solution of "chromium peroxide" File:CrO5.jpg|A dilute solution of "chromium peroxide" File:Chromium(VI) oxide peroxide (stabilized in ether phase).jpg|"chromium(VI) oxide peroxide" in ether phase (above) and chromium(III) aqueous solution (below).

References

References

1. (2002). "On the interaction of compounds of chromium(VI) with hydrogen peroxide. A study of chromium(VI) and (V) peroxides in the acid–basic pH range". Inorganica Chimica Acta.
2. (1962). "Crystal Structure of Peroxochromates, CrO₅⋅C₅H₅N". [[Nature (journal).
3. (1968). "The Crystal Structure of two Modifications of Oxidodiperoxido-2,2'-dipyridylchromium(VI), [CrO(O2)2(C10H8N2)]". Acta Chemica Scandinavica.
4. Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils; (1985). "Chromium" (in German). Lehrbuch der Anorganischen Chemie (91–100 ed.). Walter de Gruyter. pp. 1081–1095. {{ISBN. 3-11-007511-3."
5. (1986). "Chromium(VI) based oxidants-1 Chromium peroxide complexes as versatile, mild, and efficient oxidants in organic synthesis". [[Tetrahedron (journal).