Atomic Number: 24 Period Number: 4 Group Number: 6
Chromium is a steely-gray, hard metal with high melting point. There are three stable isotopes of chromium in nature - 52Cr, 53Cr and 54Cr. Chromium is remarkable for its magnetic properties: it is the only elemental solid which shows antiferromagnets ordering at room temperature.
There are many chromium compounds of Cr3+, Cr5+, Cr2+, Cr1+. Because Chromium have different colors under different circumstances, this makes foundation for its industrial uses. Lead chromate (PbCrO4), also known as chrome yellow, has been used as a yellow pigment in paints. Chromic oxide (Cr2O3), also known as chrome green, is a widely used green pigment. Rubies and emeralds also owe their colors to chromium compounds. Potassium dichromate (K2Cr2O7) is used in the tanning of leather while other chromium compounds are used as the materials, which permanently fix dyes to fabrics. Chromium compounds are also used to anodize aluminum, a process which coats aluminum with a thick, protective layer of oxide.
Physical and Chemical properties:
Atomic Weight: 51.9961
Melting Point: 2180 K
Boiling Point: 2944 K
Density: 7.15 g/cm3
Phase at Room Temperature: Solid
Ionization Energy: 6.767 eV
Oxidation States: +6, +3, +2
See also:
Wikipedia - Basics on Chromium
WebElements - The basic elements of Chromium
Jefferson Lab - Learning about Chromium
