Vanadium, a silver-white metallic element. The principal use of vanadium is as a hardening agent in alloys. In combination with iron, for example, vanadium forms an alloy that is added to steel as a hardener. Compounds of vanadium are used in the manufacture of sulfuric acid, synthetic dyes, and plastics.

Vanadium occurs in more than 65 different mineral combinations, but is never found as a pure substance. Its chief ores are carnotite (also valued for the uranium it contains), roscoelite, and vanadinite. Vanadium is also obtained as a by-product in the treatment of phosphate and iron ores, and from petroleum-refinery residues. The major producers are South Africa, Russia, China, and the United States (especially Arkansas, Utah. Idaho, and Louisiana).

Vanadium was first discovered in 1801 by Andres Manuel del Rio of Mexico, but was mistakenly thought to be a form of chromium. The metal was rediscovered in 1830 by a Swedish chemist, N. G. Sefstrm, who named it for Vanadis, Scandinavian goddess of beauty.

Symbol: V. Atomic number: 23. Atomic weight: 50.9415. Melting point: 3,434 F. (1,890 C.). Boiling point: 6,116 F. (3,380 C.). Specific gravity: 6.1. Valences: +2, 3, 4, and 5. Vanadium belongs to Group VB of the Periodic Table.