Structural characterization of cadmium hexacyanometallates(II) and relatedcomplexes

Cadmium hexacyanometallates (II) crystallize in the same monoclinic cell (s pace group C-2h(5) - P2(1/n)) reported for the analogs of manganous complex es. In that monoclinic framework, two outer cations (M = Mn2+ or Cd2+) of n eighboring structural units M-2[L-II(CN)(6)], (L = Fe-II, Ru-II, Os-II), ar e linked by two common water molecules. On heating above 100 degreesC, thes e water bridges are removed. In dehydrated complexes, the outer cation (M) remains linked to only three CN ligands. The loss of aquo-ligands induces a remarkable pi -back donation from the inner cation (L) to CN ligands, whic h was studied using IR, Raman, and Mossbauer spectroscopies.