ON THE MIXED-CRYSTALS FORMATION IN THE FE(ZN)(HCOO)(2)-CD(HCOO)(2)-H2O SYSTEM

The solubility in the Fe(HCOO)(2)-Cd(HCOO)(2)-H2O and Zn(HCOO)(2)-Cd(H COO)(2)-H2O systems have been studied by the method of physico-chemica l analysis at 25 degrees C and mixed crystals of the type Fe1-xCdx(HCO O)(2) . 2 H2O and Zn1-xCdx (HCOO)(2) . 2 H2O have been obtained. The l attice parameters of the mixed crystals have been calculated. It has b een established that the isostructural Fe(HCOO)(2) . 2 H2O and Cd(HCOO )(2) . 2 H2O form isomorphous mixed crystals, whereas the isostructura l Zn(HCOO)(2) . 2 H2O and Cd(HCOO)(2) . 2 H2O yield isodimorphous mixe d crystals. The difference in the behaviour of the two pairs of format e salts has been attributed to the difference in the Me-O-m bond lengt hs in the coordination octahedra, forming the crystal structures.