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Chromium(III) salts are compounds containing chromium in the +3 oxidation state, paired with anions such as chloride, sulfate, or nitrate. In aqueous solution, Cr3+ forms octahedral, six-coordinate complexes, commonly with water as ligands. The color of Cr3+ solutions is typically violet to purple, though ligands can alter the observed color.

Common examples include chromium(III) chloride (CrCl3), chromium(III) sulfate (Cr2(SO4)3), and chromium(III) nitrate (Cr(NO3)3). Potassium chromium alum (KCr(SO4)2·12H2O) is a historically important chromium(III) salt used as a mordant in dyeing. Hydrated and anhydrous forms exist; some salts are more soluble than others.

Uses of chromium(III) salts span pigments and tanning, among other applications. They are employed as precursors to pigments and in the production of green pigments derived from chromium compounds. They are also used as tanning agents in leather production (for example, chromium(III) sulfate) and as precursors to catalysts in organic synthesis and polymerization. They can also serve in electroplating and flame-retardant formulations in some products.

Preparation typically involves dissolving chromium-containing materials in acids to yield Cr3+ solutions, followed by crystallization of the salt. They can also be derived from the dissolution of chromium(III) oxide or from chromium metal in acid.

Safety and environmental aspects: Cr(III) salts are less toxic than hexavalent chromium compounds but can still be harmful if inhaled or ingested. Proper handling, containment, and disposal are required to prevent environmental release. In oxidizing conditions, Cr(III) can be oxidized to Cr(VI), which is highly toxic and carcinogenic.

Chromium(III) salts encompass a range of compounds with varied properties and applications; their specific identity is determined by the counter-anion and hydration state.