Copper compounds

Copper forms a rich variety of compounds, usually with oxidation states +1 and +2, which are often called cuprous and cupric, respectively.

[1] Copper compounds, whether organic complexes or organometallics, promote or catalyse numerous chemical and biological processes.

Specifically, using Benedict's reagent and Fehling's solution the presence of the sugar is signaled by a color change from blue Cu(II) to reddish copper(I) oxide.

[5] Amino acids such as cystine form very stable chelate complexes with copper(II).

[9] Monovalent copper forms luminescent CunXn clusters (where X = Br, Cl, I), exhibiting diverse optical properties.

These can undergo substitution with alkyl halides to form coupling products; as such, they are important in the field of organic synthesis.

Copper(I) forms a variety of weak complexes with alkenes and carbon monoxide, especially in the presence of amine ligands.

[20] With tetrapeptides, purple-colored copper(III) complexes are stabilized by the deprotonated amide ligands.

A sample of copper(I) oxide .
Copper(II) gives a deep blue coloration in the presence of ammonia ligands. The one used here is tetraamminecopper(II) sulfate .
Pourbaix diagram for copper in uncomplexed media (anions other than OH − not considered). Ion concentration 0.001 m (mol/kg water). Temperature 25 °C.
Ball-and-stick model of the complex [Cu(NH 3 ) 4 (H 2 O) 2 ] 2+ , illustrating the octahedral coordination geometry common for copper(II).