SYNTHESIS AND CHARACTERISATION OF DOUBLE METAL CYANIDES

Abstract

Double metal cyanides are the special class of compounds having importance in scientific and biological fields. The present work describes the synthesis of potassium hexacyanomanganate (III) and potassium hexa-cyanochromate(III) which were then used to prepare a series of complexes by replacing outer cation with zinc, copper and cobalt, respectively. In order to characterise these complexes different techniques were used. I.R. spectra revealed peaks corresponding to C N, metal - cyanide stretching, metal-cyanide bending, 0H-stretching and 0H-bending in almost all the complexes. Thermogravimetric analysis indicated the presence of water of crystallisation associated with the synthesized complexes. Magnetic studies showed paramagnetic behaviour for all the complexes with different number of unpaired electrons. Percentage of different transition metals in different complexes were calculated using AAS which were found to resemble with the proposed molecular formula. X-ray diffraction analysis showed all the complexes to be crystalline except cobalt hexacyanochromate(M) which was found amorphous in nature.