Chromium, chemical symbol Cr, atomic number 24, belongs to VI B group in the periodic table of elements.

The name of the element comes from Greek, which means "color", because all compounds of chromium have colors, and the simple substance is steel-gray metal.

In nature, it mainly exists in the form of chromite FeCr204. It is formed by reducing chromium oxide with aluminum, or electrolyzing chromite or chromic acid. According to its content in the earth's crust, chromium is one of the widely distributed elements. More cobalt, nickel, molybdenum and tungsten than previously found. This may be because the natural compounds of chromium are very stable, insoluble in water and difficult to reduce. Some people think that the metal chromium obtained by Vauclin may be chromium carbide.