Potassium tetraperoxochromate(V)

Chemical compound From Wikipedia, the free encyclopedia

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.[3] Heating this compound releases singlet oxygen.[2]

Quick facts Names, Identifiers ...
Potassium tetraperoxochromate(V)
Names
IUPAC name
Potassium tetraperoxochromate(V)
Other names
  • Potassium perchromate
  • Potassium peroxochromate
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/Cr.3K.4O2/c;;;;4*1-2/q+5;3*+1;4*-2
    Key: JSURYJVAXIVWCV-UHFFFAOYSA-N
  • [O-][O-].[O-][O-].[O-][O-].[O-][O-].[K+].[K+].[K+].[Cr+5]
Properties
K3[Cr(O2)4]
Molar mass 297.286 g/mol
Appearance red-brown crystals[1]
Melting point 70 °C (158 °F; 343 K)[2] (decomposes)
  • Poorly soluble (0 °C (32 °F; 273 K))
  • Reacts (45 °C (113 °F; 318 K))[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Close

Preparation

Potassium peroxochromate is prepared starting from chromium trioxide (CrO3), excess potassium hydroxide (KOH), and 30% hydrogen peroxide (H2O2)[4]:

2 KOH + CrO3 → K2CrO4 + H2O

Hydrogen peroxide is added at temperatures below −5 °C (23 °F; 268 K)[4]:

2 K2CrO4 + 8 H2O2 → 2 K2[Cr(O2)4] + 8 H2O

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

2 K2[Cr(O2)4] + 2 KOH → 2 K3[Cr(O2)4] + H2O2

Thus, the overall reaction is[4]:

2 K2CrO4 + 7 H2O2 + 2 KOH → 2 K3[Cr(O2)4] + 8 H2O

The compound decomposes spontaneously at higher temperatures but may be stored in sealed containers for extended periods.[2][1]

References

Related Articles

Wikiwand AI