rhodium

Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a hard, silvery-white transition metal of the platinum group. Rhodium is extremely rare and highly valued for its resistance to corrosion, high-temperature stability, and bright reflectivity, properties that make it useful in many industrial and decorative applications.

Rhodium occurs mostly in conjunction with platinum group metals in ores mined in South Africa, Russia, Canada, and the United States. It is produced as a byproduct of refining platinum and palladium. Because of its rarity and centralized production, rhodium is subject to significant price fluctuations and supply risks.

Physically, rhodium has a melting point of about 1,964°C and a boiling point near 3,695°C. It is one of the most corrosion-resistant metals, resisting attack by acids and most chemical environments. It is also highly reflective and forms a hard, durable surface layer when used as a plating.

The largest application is as a catalyst in automotive catalytic converters, where rhodium promotes the reduction of nitrogen oxides. It is also used in specialty chemical catalysts, hydrogenation reactions, and in jewelry plating to produce a bright, durable white finish. Additional uses include electrical contacts and high-precision mirrors.