sodium tris(carbonato)cobalt(III)
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| ImageFile =(Co(CO3)3)2-.svg
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|Section1={{Chembox Identifiers
| CASNo = 23311-39-9
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo_Comment = (anhydrous)
| CASNo1 = 15684-40-9
| CASNo1_Ref = {{cascite|correct|CAS}}
| CASNo1_Comment = (trihydrate)
| ChemSpiderID = 9100093
| ChemSpiderID_Comment = anhydrous
| PubChem = 10924848
| PubChem_Comment = anhydrous
| SMILES = C(=O)([O-])[O-].C(=O)([O-])[O-].C(=O)([O-])[O-].[Na+].[Na+].[Na+].[Co+3].O.O.O
| StdInChI=1S/3CH2O3.Co.3Na.3H2O/c3*2-1(3)4;;;;;;;/h3*(H2,2,3,4);;;;;3*1H2/q;;;+3;3*+1;;;/p-6
| StdInChIKey=RAXRATBBPMSPAF-UHFFFAOYSA-H
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|Section2={{Chembox Properties
| Na = 3|Co=1|C=3|O=12|H=6
| MolarMass =
| Appearance = green solid
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|Section3={{Chembox Hazards
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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.{{cite journal |doi=10.1021/cr60264a001|title=Chemistry of the Metal Carbonato Complexes |year=1970 |last1=Krishnamurty |first1=Kotra V. |last2=Mc Leod Harris |first2=Gordon. |last3=Sastri |first3=Vedula S. |journal=Chemical Reviews |volume=70 |issue=2 |pages=171–197 }}
Synthesis
An aqueous solution of cobalt(II) nitrate and hydrogen peroxide is added to a solution of sodium bicarbonate, leading to precipitation of the olive solid.{{cite book |doi=10.1002/9780470132395.ch53|chapter=Sodium Tricarbonatocobaltate(III) 3-Hydrate |year=1966 |last1=Bauer |first1=H. F. |last2=Drinkard |first2=W. C. |title=Inorganic Syntheses |pages=202–204 |volume=8 |isbn=9780470132395 }} The method is a modification of the synthesis of what has been described as “Co2(CO3)3”.{{cite journal |last1=Duval |first1=C. |title=Sur le Cobalticarbonate Cobaltique |journal=Rendus Hebdomadaires des Séances de l'Académie des Sciences |date=1930 |volume=191}}
Structure and synthetic applications
The 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,{{cite journal |doi=10.1007/s10973-009-0606-2|title=Determination of the Structural Formula of Sodium Tris-Carbonatocobaltate(III), Na3[Co(CO3)3]·3H2O by Thermogravimetry |year=2010 |last1=Tafesse |first1=Fikru |last2=Aphane |first2=Elias |last3=Mongadi |first3=Elizabeth |journal=Journal of Thermal Analysis and Calorimetry |volume=102 |pages=91–97 |s2cid=97142236 }} 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.{{cite journal |doi=10.1016/S0020-1693(02)01236-7|title=A Convenient Source of Hexaaquacobalt(III) |year=2003 |last1=Wangila |first1=Grant |last2=Jordan |first2=R.B. |journal=Inorganica Chimica Acta |volume=343 |pages=347–350 }}
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. 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)]−.{{cite book |doi=10.1002/9780470132548.ch15|title=Optically Active cis-Unidentate-Dicarbonato,cis-cis-Diunidentate-Carbonato, and Unidentate Glycinato Cobalt(III) Complexes |series=Inorganic Syntheses |year=1985 |last1=Shibata |first1=M. |chapter=Optically Active Cis -Unidentate-Dicarbonato, Cis-Cis -Diunidentate-Carbonato, and Unidentate Glycinato Cobalt(III) Complexes |pages=61–79 |volume=23|isbn=978-0-471-81873-1 }}
Other literature
- {{cite journal |doi=10.1021/ja01504a004|title=A General Synthesis of Cobalt(III) Complexes; A New Intermediate, Na3[Co(CO3)3]·3H2O |year=1960 |last1=Bauer |first1=H. F. |last2=Drinkard |first2=W. C. |journal=Journal of the American Chemical Society |volume=82 |issue=19 |pages=5031–5032 }}
- 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}}