Cuprate

Cuprates (from the Latin cuprum for copper ) are chemical compounds that contain a copper-containing anion. Here, several different types of cuprates can be distinguished.

Cuprates in complexes

Cuprate anions are formed in complexes with negatively charged ligands such as cyanide, hydroxide, or halides. Typical representatives of these complexes are Tetracyanocuprat (I), [Cu ( CN) 4 ] 3 -, tetrachlorocuprate (II ) [ CuCl4 ] 2 - or Hexahydroxocuprat (II ) [Cu (OH ) 6] 4 -. The complexes are so stable that no hydrogen sulfide with copper (II ) sulfide longer fails. There are also rare copper (III) - and copper ( IV) complexes such as Hexafluorocuprat (III) [ CuF6 ] 3 - or Hexafluorocuprat (IV) [ CuF6 ] 2 - which are strong oxidizing agents.

Even complexes with organic ligands are known, but these are not the cuprates due to its neutral charge on, but the copper chelates.

Copper complexes often show a characteristic color. Copper ( I) complexes are red - brown, copper (II ) complexes turquoise to deep blue, copper ( III) - and copper (IV ) complexes orange-red.

Organic cuprates

Cuprates play an important role in organic copper compounds. They thereby contain the R2Cu - anion. Depending on the available counterion distinction is made ​​between Gilman ( with lithium as the counterion ), Normant ( magnesium and a halide as a counter ion ) and Knochelcupraten (zinc and a halide as a counter ion, an organic radical is replaced by cyanide).

Salt-like cuprates

The otherwise rare in copper oxidation state III comes in the CuO2 - before anion. This occurs, for example in YBCO and plays in an important role for the high-temperature superconductivity.