Cobalt(III) nitrate explained

Cobalt(III) nitrate is an inorganic compound with the chemical formula Co(NO₃)₃.^[1] It is a green, diamagnetic solid that sublimes at ambient temperature.

Structure

The compound is a molecular coordination complex. The three bidentate nitrate ligands give a distorted octahedral arrangement. The nitrate ligands are planar. With D₃ symmetry, the molecule is chiral. The Co-O bond lengths are about 190 pm long. The O-Co-O angles for the chelating oxygen atoms in the same nitrate anion is about 68 degrees. The same geometry seems to persist in carbon tetrachloride solution.^[2]

Preparation and reactions

Cobalt(III) nitrate can be prepared by the reaction of dinitrogen pentoxide with cobalt(III) fluoride .^[2] It can be purified by vacuum sublimation at 40 °C.^{[3] [4]}

Cobalt(III) nitrate oxidizes water, the initial green solution rapidly turns pink, with formation of cobalt(II) ions and release of oxygen.^[1] Cobalt(III) nitrate can be intercalated in graphite, in the ratio of 1 molecule for each 12 carbon atoms.^[4]

See also

• Cobalt(III) fluoride
• Cobalt(III) chloride
• Cobalt(III) hydroxide
• Iron(III) nitrate
• Iron(III) oxalate

Notes and References

1. W. Levason and C. A. McAuliffe (1974): "Higher oxidation state chemistry of iron, cobalt, and nickel". Coordination Chemistry Reviews, volume 12, issue 2, pages 151-184.
2. R. J. Fereday, N. Logan and D. Sutton (1969): "Anhydrous cobalt(III) nitrate: preparation, spectra, and reactions with some organic ligands". Journal of the Chemical Society A: Inorganic, Physical, Theoretical, volume 1969, issue 0, pages 2699-2703.
3. J. Hilton and S. C. Wallwork (1968): "The crystal structure of cobalt(III) nitrate", Chemical Communications, volume 1968, issue 15, pages 871-871.
4. E. Stumpp, G. Nietfeld, K. Steinwede, and K. D. Wageringel (1983) "Reaction of anhydrous metal nitrates with graphite". Synthetic Metals, Evolume 7, issues 1–2, pages 143-151.