Chrome alum

Chrome alum, also known as chromium potassium sulfate, is a chemical compound. Its chemical formula is KCr(SO4)2. It contains chromium, potassium, and sulfate ions. The chromium is in its +3 oxidation state.

Properties
It is a dark purple solid. It is normally attached to extra water molecules. It dissolves in water.

Preparation
It is made by reducing potassium dichromate with sulfur dioxide.

Uses
It was used in making leather; now chromium(III) sulfate is used instead. 

Related pages
Alum
Aluminium sulfate

Category:Potassium compounds
Category:Sulfates
Category:Chromium compounds