Cobalt(III) nitrate


Cobalt nitrate is an inorganic compound with the chemical formula Co3.

Properties

Cobalt nitrate is a stable green crystalline solid, that sublimates at ambient temperature. It is soluble in chloroform.

Structure

The molecular structure has three nitrate groups in bidentate coordination with the cobalt atom, which is thus bonded to six oxygen atoms in a distorted octahedral arrangement. The nitrates are approximately planar, and lie on three mutually perpendicular planes, resulting in a chiral molecule. The Co-O bonds are about 190 pm long. The O-Co-O angles for the two oxygens in the same nitrate is about 68 degrees. The same geometry seems to persist in carbon tetrachloride solution.

Preparation

Cobalt nitrate can be prepared by the reaction of dinitrogen pentoxide with cobalt fluoride . It can be purified by vacuum sublimation at 40 °C.

Reactions

Cobalt nitrate is soluble in water, giving a green solution that rapidly turns pink, with formation of cobalt ions and release of oxygen.
Cobalt nitrate can be intercalated in graphite, in the ratio of 1 molecule for each 12 carbon atoms, by heating the two substances at 40 °C for 3 hours.