CRYSTAL-STRUCTURE AND MOSSBAUER SPECTROSCOPIC STUDY OF FESNF6-CENTER-DOT-6H2O

Large single crystals of FeSnF6 . 6H(2)O were grown when aqueous hydrofluoric solutions of SnF2 and FeF2 were allowed to evaporate in air. Tin-119 Mossbauer spectroscopy at ambient temperature shows a single line at slightly negative isomer shift relative to CaSnO3 at room temperature (delta = -0.380(6) mm/s, Delta = 0). This is characteristic of tetravalent tin octahedrally coordinated by fluorine. The X-ray crystal structure shows that tin(IV) is coordinated by 6 fluorine atoms, and Fe(II) by 6 water molecules. Both sites show a slight distortion from octahedral symmetry: the six distances are equal (Sn-Fe = 1.941(3) Angstrom and Fe-O = 2. 112(3) Angstrom), whereas there are two values of angles (Fe-Sn-F = 90.4(1)degrees and 89.6(1)degrees; O-Fe-O = 91.1(1)degrees and 88.9(1)degrees). The material is an ionic compound [SnF6](2-)[Fe(H2O)(6)](2+).