Potassium hexanitritocobaltate(III) is a salt with the formula K₃ o(NO₂)₆ It is a yellow solid that is poorly soluble in water. The compound finds some use as a yellow pigment under the name Indian Yellow. The salt features potassium cations and an trianionic

coordination complex A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as '' ligands'' or complexing agents. ...

. In the anion, cobalt is bound by six nitrito ligands, the overall complex having octahedral molecular geometry. The oxidation state of cobalt is 3+. Its low-spin d⁶ configuration confers kinetic stability and diamagnetism. The compound is prepared by combining cobalt(II) and nitrite salts in the presence of oxygen. The corresponding sodium cobaltinitrite is significantly more soluble in water. The compound was first described in 1848 by

Nikolaus Wolfgang Fischer Nikolaus Wolfgang Fischer (15 January 1782 – 19 August 1850) was a German chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemis ...

in Breslau, and it is used as a yellow pigment called

Aureolin Aureolin (sometimes called cobalt yellow) is a pigment sparingly used in oil and watercolor painting. Its color index name is PY40 (40th entry on list of yellow pigments). It was first made in 1831 by Nikolaus Wolfgang Fischer in Breslau character ...

References

Potassium compounds Cobalt compounds Nitrites Coordination complexes {{inorganic-compound-stub

See also

References