Synthesis and thermal decomposition of double complex compounds containing anion [FeMn(CN) 6] 2-

Synthesis and thermal decomposition of double complex compounds [Ni 2(en) 3(H 2O) 6][FeMn(CN) 6] 2·xH 2O (I) and [Cu(en)(H 2O) 2][FeMn(CN) 6] 2·xH 2O (II) have been studied. The thermolysis has been carried out in oxidizing (air), inert (argon) and reducing (hydrogen) atmosphere in the temperature range 20-1000 °C. The composition of solid and gaseous products of thermolysis has been studied. It has been shown that the carbon of ligands in air is removed as CO and CO 2, while ammonia escapes as a degradation product of ethylenediamine. The solid residues are mixtures of the central ion oxides. There is slight evolution of CO and ammonia in the argon atmosphere. The solid residues in argon are nickel, manganese and copper ferrocyanides, intermetallic NiFe, Cu, FeC and MnO. In the hydrogen atmosphere the most of nitrogen is emitted in the form of ammonia. The residual carbon content in the residues of calcination at 900 °C is less than 1 %. The thermolysis in the hydrogen atmosphere produces the highly disperse tri- and bimetallic phases, which are easily oxidized in air to NiFe+MnO and Cu+FeC+FeO+MnO.