Potassium tetraperoxochromate(V)

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]

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
CompTox Dashboard (EPA)	DTXSID5059531
InChI InChI=1S/Cr.3K.4O2/c;;;;4*1-2/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	black
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

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.