kobaltkrom

Kobaltkrom is the common name for a cobalt-containing chromate compound known for its colored properties and historical use as a pigment. The term appears in technical literature and in discussions of inorganic pigments, especially in German-language sources where "Kobaltkrom" is used.

Chemical composition and structure: In its simplest form, kobaltkrom denotes cobalt(II) chromate with the formula CoCrO4. It consists of divalent cobalt cations (Co2+) and chromate anions (CrO4^2-) in a crystalline lattice. The solid is typically prepared as a fine powder or as pigments embedded in glassy matrices and ceramics. Color can vary due to particle size, hydration state, and impurities.

Preparation and forms: It can be produced by precipitating cobalt(II) salts with chromate sources in aqueous solution, followed by filtration and drying, or by high-temperature solid-state synthesis. In pigment use, it is often incorporated into glaze or frit formulations.

Applications and properties: Kobaltkrom has been valued as a stable inorganic pigment with good heat resistance, suitable for ceramics, glass, and specialty coatings. It is relatively insoluble in water, contributing to durable color. However, the predominant chromium in chromates is hexavalent (Cr(VI)), which poses health and environmental risks.

Safety and regulation: Cr(VI) compounds are toxic and carcinogenic; cobalt compounds can cause irritation and sensitization. Handling requires appropriate PPE, ventilation, and waste management per regulatory guidelines.

See also: cobalt pigments, chromates, inorganic pigments.