Chromium

Chromium
Chromium main uses are in alloys such as stainless steel, in chrome plating and in metal ceramics. Chromium plating was once widely used to give steel a polished silvery mirror coating. Chromium is used in metallurgy to impart corrosion resistance and a shiny finish; as dyes and paints, its salts colour glass an emerald green and it is used to produce synthetic rubies; as a catalyst in dyeing and in the tanning of leather; to make molds for the firing of bricks. Chromium (IV) oxide (CrO2) is used to manufacture magnetic tape.

Chemical Composition

Atomic number	24
Atomic mass	51.996 g.mol -1
Electronegativity	1.6
Density	7.19 g.cm-3 at 20°C
Melting point	1907 °C
Boiling point	2672 °C
Vanderwaals radius	0.127 nm
Ionic radius	0.061 nm (+3) ; 0.044 nm (+6)
Isotopes	6
Electronic shell	[ Ar ] 3d5 4s1
Energy of first ionisation	651.1 kJ.mol -1
Energy of second ionisation	1590.1 kJ.mol -1
Energy of first ionisation	2987 kJ.mol -1
Standard potential	- 0.71 V (Cr3+ / Cr )