Peroxo compounds of Chromium (VI)
When Cr6+ reacts with H2O2, the product depends on the pH and [Cr6+]:
In acidic solution:
CrO(O2)2 is formed. It is a deep blue – violet compound which decomposed rapidly in aqueous solution to Cr3+ + O2.
CrO(O2)2 can extracted into ether and form adduct with pyridine.
In less acidic solutions:
The product is violet, diamagnetic and explosive compound. Its structure are thought to contain [CrO(O2)(OH)]-
In alkaline solution:
a red – brown compound K3CrO8 is formed with a structure contains four groups from peroxo group.