J. C. Dewan, A. J. Edwards, J. Guy
1986
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0
Influential Citations
7
Citations
Journal
Journal of The Chemical Society-dalton Transactions
Abstract
The crystal structures of potassium tetrafluorochromate(III), K[CrF4](1), and dipotassium dichlorohexafluorotrichromate(II), K2[Cr3Cl2F6](2), are reported. The structure of (1) consists of infinite triangular anionic columns comprising approximately planar Cr3F9 units linked above and below by fluoride bridges, the columns being separated by K+ ions. Each CrIII atom is octahedrally co-ordinated by six F atoms. The structure of (2) contains two crystallographically independent CrII atoms which have distorted octahedral co-ordination by four equatorial F atoms and two axial Cl atoms. The Cr atoms are linked together by single Cr–F–Cr bridges and also by a novel chloride fluoride double bridge. The structure can also be thought of as comprising two-dimensional CrF2 sheets, held together by Cl atom bridges. Charge balance is maintained by K+ ions. Crystal data for (1) are: a= 15.76(1), b= 7.43(1), c= 18.38(1)A, Z= 24, orthorhombic, space group Pnma, final R= 0.041 for 1 975 diffractometer data with Io > 3σ(Io). Crystal data for (2) are: a= 6.726(1), b= 11.157(5), c= 7.391(3)A, β= 125.31(4)°, Z= 2, monoclinic, space group P21/c, final R= 0.041 for 1 044 diffractometer data with Io > 2σ(Io).