Sodium tris(carbonato)cobalt(III) is the inorganic compound with the formula Na3Co(CO3)3•3H2O. The salt contains an olive-green metastable cobalt(III) coordination complex. The salt, a homoleptic metal carbonato complex, is sometimes referred to as the “Field-Durrant precursor” and is prepared by the “Field-Durrant synthesis”. It is used in the synthesis of other cobalt(III) complexes. Otherwise cobalt(III) complexes are generated from cobalt(II) precursors, a process that requires an oxidant.[1]
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3D model (JSmol)
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| C3H6CoNa3O12 | |
| Molar mass | 361.972 g·mol−1 |
| Appearance | green solid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis
editAn aqueous solution of cobalt(II) nitrate and hydrogen peroxide is added to a solution of sodium bicarbonate, leading to precipitation of the olive solid.[2] The method is a modification of the synthesis of what has been described as “Co2(CO3)3”.[3]
Structure and synthetic applications
editThe identity of this complex anion is uncertain, suggestions include [Co(κ2-CO3)3]3-, [Co(κ1-CO3H)3(OH)3]3-, and [Co(κ2-CO3)2(κ1-CO3)(OH2)]3-. Thermal gravimetric analysis favors the presence of one aquo ligand,[4] and infra-red spectroscopy indicates the presence of both bi- and unidentate carbonate ligands. The addition of [Co(NH3)6]Cl3 to fresh solutions of sodium tris(carbonato)cobalt(III) precipitates anhydrous salt [Co(NH3)6] [Co(κ2-CO3)3]. This salt has been characterized by X-ray crystallography, which established that the anionic complex features three bidentate (κ2-) carbonate ligands.[5]
To some extent, the exact description of the title salt is unimportant since it is only used as a synthetic intermediate, it has no intrinsic value. Products include [Co(H2O)6]3+, [Co(κ2-CO3)(H2O)4]+, and [Co(κ2-CO3)2(H2O)2]− and their derivatives where the aquo ligand has been displaced.[5] The closely related potassium tris(carbonatocobalt(III) has also been used for the preparation of diverse complexes. These derivatives include [Co(NH3)2(κ2-CO3)2]− and [Co(CN)2(κ2-CO3)2]3-, rare examples of biscarbonato cobalt(III) complexes. Other derivatives include the dinitrite [Co(NH3)2(κ2-CO3)(NO2)2]− and the oxalate [Co(NH3)2(κ2-CO3)(C2O4)]−.[6]
Other literature
edit- Bauer, H. F.; Drinkard, W. C. (1960). "A General Synthesis of Cobalt(III) Complexes; A New Intermediate, Na3[Co(CO3)3]·3H2O". Journal of the American Chemical Society. 82 (19): 5031–5032. doi:10.1021/ja01504a004.
- Fikru Tafesse, Elias Aphane, and Elizabeth Mongadi (2009): "Determination of the structural formula of sodium tris-carbonatocobaltate(III), Na3[Co(CO3)3]·3H2O by thermogravimetry". Journal of Thermal Analysis and Calorimetry, volume 102, issue 1, pages 91–97. doi:10.1007/s10973-009-0606-2
- Thomas P. McCutcheon and William J. Schuele (1953): "Complex Acids of Cobalt and Chromium. The Green Carbonatocobalt(III) Anion". Journal of the American Chemical Society, volume 75, issue 8, pages 1845–1846. doi:10.1021/ja01104a019
References
edit- ^ Krishnamurty, Kotra V.; Mc Leod Harris, Gordon.; Sastri, Vedula S. (1970). "Chemistry of the Metal Carbonato Complexes". Chemical Reviews. 70 (2): 171–197. doi:10.1021/cr60264a001.
- ^ Bauer, H. F.; Drinkard, W. C. (1966). "Sodium Tricarbonatocobaltate(III) 3-Hydrate". Inorganic Syntheses. Vol. 8. pp. 202–204. doi:10.1002/9780470132395.ch53. ISBN 9780470132395.
- ^ Duval, C. (1930). "Sur le Cobalticarbonate Cobaltique". Rendus Hebdomadaires des Séances de l'Académie des Sciences. 191.
- ^ Tafesse, Fikru; Aphane, Elias; Mongadi, Elizabeth (2010). "Determination of the Structural Formula of Sodium Tris-Carbonatocobaltate(III), Na3[Co(CO3)3]·3H2O by Thermogravimetry". Journal of Thermal Analysis and Calorimetry. 102: 91–97. doi:10.1007/s10973-009-0606-2. S2CID 97142236.
- ^ a b Wangila, Grant; Jordan, R.B. (2003). "A Convenient Source of Hexaaquacobalt(III)". Inorganica Chimica Acta. 343: 347–350. doi:10.1016/S0020-1693(02)01236-7.
- ^ Shibata, M. (1985). "Optically Active Cis -Unidentate-Dicarbonato, Cis-Cis -Diunidentate-Carbonato, and Unidentate Glycinato Cobalt(III) Complexes". Optically Active cis-Unidentate-Dicarbonato,cis-cis-Diunidentate-Carbonato, and Unidentate Glycinato Cobalt(III) Complexes. Inorganic Syntheses. Vol. 23. pp. 61–79. doi:10.1002/9780470132548.ch15. ISBN 978-0-471-81873-1.