Potassium tetraperoxochromate(V)

Potassium tetraperoxochromate(V)
Names

IUPAC name Potassium tetraperoxochromate(V)
Other names Potassium perchromate Potassium peroxochromate
Identifiers
CAS Number	12331-76-9^Y
3D model (JSmol)	Interactive image
ChemSpider	106513
PubChem CID	139134081
InChI InChI=1S/Cr.3K.4O2/c;;;;41-2/q+5;3+1;4*-2 Key: JSURYJVAXIVWCV-UHFFFAOYSA-N
SMILES [O-][O-].[O-][O-].[O-][O-].[O-][O-].[K+].[K+].[K+].[Cr+5]
Properties
Chemical formula	K₃[Cr(O₂)₄]
Molar mass	297.286 g/mol
Appearance	red brown
Melting point	70 °C (158 °F; 343 K)^[1] (decomposes)
Solubility in water	Poorly soluble (0 °C) Reacts (45 °C)^[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) Infobox references

Potassium peroxochromate, potassium tetraperoxochromate(V), or simply potassium perchromate, is an inorganic compound having the chemical formula K₃[Cr(O₂)₄]. It is a red-brown paramagnetic solid. It is the potassium salt of tetraperoxochromate(V), one of the few examples of chromium in the +5 oxidation state and one of the rare examples of a complex stabilized only by peroxide ligands.^[2] This compound is used as a source of singlet oxygen.^[1]

Preparation

Potassium peroxochromate is prepared by treating potassium chromate with hydrogen peroxide at 0 °C:

2 CrO2−4 + 8 H₂O₂ → 2 [Cr(O₂)₄]²⁻ + 8 H₂O

The intermediate tetraperoxochromate(VI) is reduced by hydrogen peroxide, forming tetraperoxochromate(V):^[3]^[4]

2 [Cr(O₂)₄]²⁻ + 2 OH⁻ + H₂O₂ → 2 [Cr(O₂)₄]³⁻ + 2 H₂O + O₂

Thus, the overall reaction is:

2 CrO2−4 + 9 H₂O₂ + 2 OH⁻ → 2 [Cr(O₂)₄]³⁻ + 10 H₂O + O₂

The compound decomposes spontaneously at higher temperatures.

References

^ ^a ^b ^c John W. Peters; Paul J. Bekowies; Arthur M. Winer; James N. Pitts Jr. (1975). "Potassium perchromate as a source of singlet oxygen". Journal of the American Chemical Society. ACS Publications. 97 (12): 3299–3306. doi:10.1021/ja00845a003.
^ Sergienko, V. S. (2007). "Structural chemistry of peroxo compounds of group VI transition metals: I. Peroxo complexes of chromium". Crystallography Reports. 52 (4): 639–646. Bibcode:2007CryRp..52..639S. doi:10.1134/S1063774507040116. S2CID 95018505.
^ Haxhillazi, Gentiana. "Preparation, Structure and Vibrational Spectroscopy of Tetraperoxo Complexes of Cr^V+, V^V+, Nb^V+ and Ta^V+". Archived from the original on 2011-07-18. Retrieved 2009-03-07.
^ Riesenfeld, E. H.; Wohlers, H.E.; Kutsch, W.A. (1905). "Höhere Oxydationsproducte des Chroms". Berichte der Deutschen Chemischen Gesellschaft. 38 (2): 1885–1898. doi:10.1002/cber.190503802113.