Synthesis, Crystal Structure, and Thermal Decomposition of [M(NH3)6]4[Fe(CN)6]3·12H2O (M = Ir, Rh) in Different Atmospheres

New double complex salts [Ir(NH3)6]4[Fe(CN)6]3·12H2O and [Rh(NH3)6]4[Fe(CN)6]3·12H2O were synthesized and structurally characterized for the first time. The thermal behavior of the synthesized salts in reducing (He/H2), inert (He), and oxidizing (Ar/O2) atmospheres was studied in detail. The final product of the decomposition of double complex salts [Ir(NH3)6]4[Fe(CN)6]3·12H2O in reducing and inert atmospheres is a mixture of face-centered cubic and hexagonal close-packed nanosized solid solutions of Ir-Fe and amorphous carbon. The decomposition of [Rh(NH3)6]4[Fe(CN)6]3·12H2O in the same atmospheres leads to the formation of a mixture of ordered and disordered Rh-Fe nanoalloys containing amorphous carbon. In an oxidizing atmosphere, a mixture of metal oxides and metallic iridium (or rhodium) is formed. Based on the data obtained, thermal decomposition of [Ir(NH3)6]4[Fe(CN)6]3·12H2O and [Rh(NH3)6]4[Fe(CN)6]3·12H2O can be considered as a method for producing nanoalloys or oxide systems based on iron and iridium (rhodium).