What Is Chromium Hydroxide?
Chromium hydroxide exists in different forms based on the oxidation state of chromium. The most commonly used and sold form is trivalent chromium hydroxide. Trivalent chromium hydroxide is an amphoteric hydroxide, meaning it can react with both acids and bases. It is insoluble in water and dilute acids but can dissolve in strongly acidic or strongly basic solutions. This compound typically appears as a blue or green solid powder.
Chromium hydroxide forms as a blue precipitate when chromium ions in an aqueous solution react with hydroxide ions. While chromium hydroxide itself is nonflammable, it decomposes upon heating to produce chromium oxide.
Uses of Chromium Hydroxide
Chromium hydroxide is primarily used as a pigment due to its excellent resistance to light, acids, and alkalis. Its bright blue-green color is more vibrant than chromium oxide, making it particularly valuable in the cosmetics industry for products such as makeup, hair colorants, nail paints, and skin care products.
Additionally, chromium hydroxide has been utilized as a water-soluble preservative for wood, favored for its fixation, preservative, and antiseptic properties. However, its usage has declined due to environmental concerns.