Percobaltates are chemical compounds where the oxidation state of cobalt is +5. This is the highest established oxidation state of cobalt.1 The simplest of these are bi-metallic Group 1 oxides such as sodium percobaltate (Na3CoO4); which may be produced by the reaction of cobalt(II,III) oxide and sodium oxide, using oxygen as the oxidant:
- 4 Co3O4 + 18 Na2O + 7 O2 → 12 Na3CoO4
The potassium salt can be synthesized similarly; its magnetic moment has indicated the existence of cobalt(V).23 No crystallographic analysis has been reported for either material. Percobaltates can be stabilized by use of oxides or fluorides.
A number of organometallic Co(V) complexes have also been reported.1
References
References
- Riedel, Sebastian; Kaupp, Martin (March 2009). "The highest oxidation states of the transition metal elements". Coordination Chemistry Reviews. 253 (5–6): 606–624. doi:10.1016/j.ccr.2008.07.014.
- Brendel, Claus; Klemm, Wilhelm (January 1963). "Weitere Versuche zur Darstellung von Kaliumcobaltat (V)". Zeitschrift für anorganische und allgemeine Chemie (in German). 320 (1–4): 59–63. doi:10.1002/zaac.19633200109.
- D. Nicholls (2 October 2013). The Chemistry of Iron, Cobalt and Nickel: Comprehensive Inorganic Chemistry. Elsevier Science. pp. 1107–. ISBN 978-1-4831-4643-0.