Potassium hypochromate is a chemical compound with the formula K3CrO4 with the unusual Cr5+ ion.

This compound is unstable in water but stable in alkaline solution[1] and was found to have a similar crystal structure to potassium hypomanganate.

[2] This compound is commonly prepared by reacting chromium(III) oxide and potassium hydroxide at 850 °C under argon:[2] This compound can be prepared other ways such as replacing chromium oxide with potassium chromate.

[1] Potassium hypochromate decomposes in water to form chromium(III) oxide and potassium chromate when alkali is not present or low.

[1] Potassium hypochromate also reacts with acids such as hydrochloric acid to form chromium(III) oxide, potassium chromate, and potassium chloride:[2] Other reducing agents such as hydroperoxides can oxidize the hypochromate ion into chromate ions.