Studies on mixed metal(II)–iron(II) chloride systems. Part 2. Mössbauer and X-ray powder diffraction data for the potassium and rubidium M′M″xFe1–xCl3·2H2O (M′= K or Rb; M″= Mn, Co, or Ni; x= 0.5) systems

Abstract

The potassium and rubidium complexes M′M″_xFe_1–x·2H₂O (M′= K or Rb; M″= Mn, Co, or Ni; x= 0.5) have been studied by Mössbauer spectroscopy and X-ray powder diffraction. The first occurrence of an octahedral Fe^II environment containing four chlorides and two cis water molecules is reported for the Rb materials. The K materials contain octahedral Fe^II environments with trans water molecules. The ⁵⁷Fe Mössbauer data for these compounds are presented. The chemical shifts of both sets of materials are similar, but the quadrupole splitting data are different. The data for the Rb materials are explained in terms of changes in site symmetry and orbital occupancy. The changes are brought about by changes in bonding due to ‘ pressure ’ effects. The occurrence of cis–trans isomers in the mother-solutions is discussed.