Direct synthesis of alkali trifluorocobaltate(II) monohydrates, A[CoF3].H2O (A = NH4, Na, or K). First synthesis and structural assessment of mixed-ligand fluoro complexes of cobalt(II), [Co(NH3)4F2] and A[CoF(SO4)(H2O)2](A = NH4, Na, or K)

Bhattacharjee, Manabendra N. ; Chaudhuri, Mihir K. ; Devi, Meenakshi ; Yhome, Khriesavilie (1987) Direct synthesis of alkali trifluorocobaltate(II) monohydrates, A[CoF3].H2O (A = NH4, Na, or K). First synthesis and structural assessment of mixed-ligand fluoro complexes of cobalt(II), [Co(NH3)4F2] and A[CoF(SO4)(H2O)2](A = NH4, Na, or K) Journal of the Chemical Society, Dalton Transactions (5). pp. 1055-1057. ISSN 0300-9246

Full text not available from this repository.

Official URL: http://www.rsc.org/publishing/journals/DT/article....

Related URL: http://dx.doi.org/10.1039/DT9870001055

Abstract

Alkali trifluorocobaltate(II) monohydrates, A[CoF3].H2O (A = NH4, Na, or K), have been synthesised directly from the reaction of Co(OH)2 and alkali fluorides in 40% HF followed by precipitation with ethanol at pH<3. While a higher pH (5-6), maintained by the addition of AOH, contaminates the product for A = Na or K, a molecular complex [Co(NH3)4F2] is formed in the case where aqueous ammonia is used to raise the pH. The synthesis of mixed fluorocobaltates(II) of the type A[CoF(SO4)(H2O)2](A = NH4, Na, or K) has been achieved by reacting Co(OH)2 with AF and A2SO4, in the ratio 1 : 2 : 1, in the presence of a very small amount of 40% HF at a steam-bath temperature. The compounds were isolated by the addition of ethanol. The compounds have been characterised from the results of elemental analyses, pyrolysis at 120 °C, magnetic susceptibility measurements, i.r., laser Raman, and electronic spectroscopic studies. While the magnetic moments and electronic spectra of [Co(NH3)4F2] and [CoF(SO4)(H2O)2]- suggest an octahedral or a distorted-octahedral environment for cobalt(II), i.r. and laser Raman spectra provide evidence for the occurrence of a bridging bidentate sulphate ligand in the latter.

Item Type:Article
Source:Copyright of this article belongs to Royal Society of Chemistry.
ID Code:23553
Deposited On:25 Nov 2010 13:48
Last Modified:30 May 2011 07:42

Repository Staff Only: item control page