II.

Properties and Occurrence

Vanadium takes a high polish and is one of the hardest of all metals. It melts at about 1910°C (about 3470°F), boils at about 3407°C (about 6164°F), and has a specific gravity of 6.11. The atomic weight of vanadium is 50.94. Vanadium is soluble in nitric and sulfuric acids and insoluble in hydrochloric acid, dilute sodium hydroxide, and dilute alcohol. Vanadium forms several acidic oxides, the most important of which are the dark green trioxide, V₂O₃, and the orange pentoxide, V₂O ₅. Other important compounds include vanadium monosulfide, VS; vanadium trisulfide, V₂S₃; vanadium dichloride, VCl₂; vanadium trichloride, VCl₃; vanadium dihydroxide, V(OH)₂; and metavanadic acid, HVO₃.

Vanadium ranks about 19th in abundance of the elements in Earth's crust. It is never found in the pure state, but occurs in combination with various minerals throughout the world. Vanadium-ore minerals in the United States are roscoelite, found in Colorado; vanadinite, found in Arizona and New Mexico; and carnotite, found in Colorado and Utah. Major producers of vanadium include the United States, Russia, and South Africa.