Chromium(III) perchlorate is an inorganic compound, a salt with the chemical formula Cr(ClO<sub>4</sub>)<sub>3</sub>. It has many hydrates, including a hexahydrate Cr(ClO<sub>4</sub>)<sub>3</sub>÷6H<sub>2</sub>O and a nonahydrate Cr(ClO<sub>4</sub>)<sub>3</sub>÷9H<sub>2</sub>O. They water-soluble cyan solids.
Chromium perchlorate can be prepared by reacting chromium(III) oxide or chromium(III) hydroxide with perchloric acid:
Chromium perchlorate reacts with NH<sub>3</sub> in suitable conditions to form an orange hexammine complex Cr(ClO<sub>4</sub>)<sub>3</sub>÷6NH<sub>3</sub>. Other compounds with the general formula Cr(ClO<sub>4</sub>)<sub>3</sub>(NH<sub>3</sub>)<sub>x</sub> are known. When x = 3, the compound is red, when x = 4 or 5, it is orange. The hexammine complex will explode.
It forms complexes with N<sub>2</sub>H<sub>4</sub>, such as purple Cr(ClO<sub>4</sub>)<sub>3</sub>÷2N<sub>2</sub>H<sub>4</sub>.
It can also form complexes with urea (CO(NH<sub>2</sub>)<sub>2</sub>), such as Cr(ClO<sub>4</sub>)<sub>3</sub>÷6CO(NH<sub>2</sub>)<sub>2</sub> with a hexagonal structure.