What is Chrome alum?
[[File:Chromium(III) Potassium Sulfate-crystals.jpg|thumb|Chrome alum]] '''Chrome alum''', also known as '''chromium potassium sulfate''', is a [[chemical compound]]. Its chemical formula is KCr(SO<sub>4</sub>)<sub>2</sub>. It contains [[chromium]], [[potassium]], and [[sulfate]] [[ion]]s. 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 [[reduction (chemistry)|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]] {{chem-stub}} [[Category:Potassium compounds]] [[Category:Sulfur compounds]] [[Category:Chromium compounds]]