Chromium is a transition metal in Group VIB and the 4th period. Other members of the group are molybdenum (Mo) and tungsten (W).

Vauquelin was the first to isolate chromium salts, mercuric chromate and lead chromate, in 1797. In the following year, he prepared the free metal by reducing chromium trioxide with charcoal.

The name is derived from the Greek word, chroma, for color, because of the element's many colored compounds. The symbol Cr is an abbreviation of the name.

Chromium is a steel gray, lustrous, hard metal that takes a high polish. In the solid state the metal has a kubinę centruotojo tūrio struktūrą.

Traces of chromium oxide in aluminum oxide give rubies. Similarly, traces in aluminum beryllium silicates give emeralds. The principal ore is chromite [(Fe,Mg)Cr₂O₄], which is found in Southern Rhodesia, Russia, Republic of South Africa, Cuba, New Caledonia, and the Philippines.

Chromium metal is produced by reducing the oxide with aluminum

Cr₂O₃(k) + 2 Al(k) 2 Cr(k) + Al₂O₃(k)

in a reaction similar to the thermite reaction (the reduction of iron(III) oxide with aluminum.)

Chromium is used to harden steel, to manufacture stainless steel (11-18% chromium), and to form many very useful alloys. Much is used in plating to produce a hard, beautiful surface and to prevent corrosion.

All compounds of chromium are colored; the most important are the chromates of sodium and potassium, the dichromates, and the potassium and ammonium chrome alums.

The dichromates are used as oxidizing agents in quantitative analysis. These compounds are salts of chromic acid and are used as pigments in paints, in dyeing, and in the tanning of leather. Chrome yellow, a pigment, consists largely of lead chromate.

Chromium compounds are used in the textile industry as mordants (to fix dye colors in fabrics), and by the aircraft and other industries for anodizing aluminum.

The refractory industry has found chromite useful for forming bricks and shapes, as it has a high melting point, moderate thermal expansion, and a stable crystalline structure. Finally, chromium(IV) oxide is the magnetic material in certain recording tapes.