Chromium(III) hydroxide

Chromium(III) hydroxide is a gelatinous green inorganic compound with the chemical formula Cr(OH)3. It is a polymer with an undefined structure and low solubility. It is amphoteric, dissolving in both strong alkalis and strong acids.
 * In alkali:
 * In acid:

It is used as a pigment, as a mordant, and as a catalyst for organic reactions.

It is manufactured by adding a solution of ammonium hydroxide to a solution of chromium salt.

Pure Cr(OH)3 is as yet (2020) unknown among the mineral species. However, three natural polymorphs of the oxyhydroxide, CrO(OH), are known: bracewellite, grimaldiite and guyanaite.