Copper

Key information

Atomic number:

Atomic weight:

Density:

8960 kg/m³

Boiling point:

2868.16° K

Melting point:

1356.16° K

Heat vapour:

304.86 kJ/mol

Heat fusion:

13.02 kJ/mol

Thermal conductivity:

59.3 W/m/K

Specific heat capacity:

393.63 J/kg/K

Copper, one of the seven metals of alchemy, takes its name from the Latin cyprium (Cyprus). It has two main oxidation states:

Cuprite (Cu₂O) is copper(I) oxide.
Tenorite CuO is copper (II) oxide.

Copper with a charge of +1 is called cuprous; with a +2 charge it is called cupric. Copper (II) carbonate (often called copper carbonate or cupric carbonate) occurs naturally as malachite (CuCO₃.Cu(OH)₂) and azurite (Cu₃(CO₃)₂(OH)₂).

Copper does not react in water, although it is subject to oxidation in air, which gives the metal a familiar green or brown patina.

Light Transmission

The colours of copper(II) complexes are explained by the behaviour of visible light passing through an aqueous solution. The visible spectrum for a solution of Cu(II), [Cu(H₂O)₆]²⁺, has an absorption band which spans the red-orange-yellow portion of the spectrum. Green, blue and violet are transmitted by a solution. So in relationship to the artist's colour wheel - colours on one side of the wheel are absorbed and their complementary colours are transmitted within a solution of copper sulphate.

Valency: