Double complex salts [Pd(NH3)4]3[Rh(NO2)6]2, [Pd(NH3)4]3[Rh(NO2)6]2·H2O as promising precursors to prepare Pd-Rh nanoalloys

Two new double complex salts [Pd(NH3)4]3[Rh(NO2)6]2 (I) and [Pd(NH3)4]3[Rh(NO2)6]2·H2O (II) are synthesized and characterized. The techniques to produce one-phase residues of the salts are developed. The crystallographic data for I: a = 18.915(2) Å, V = 6767.4 Å3, F-43c space group, Z = 8, dx = 2.548 g/cm3; II: a = 21.160(6) Å, b = 8.085(7) Å, c = 21.363(4) Å, β = 91.71(4)°, V = 3661.1(6) Å3, P21/c space group, dx = 2.357 g/cm3. Thermal properties of the obtained compounds in the hydrogen and helium atmosphere are studied. It is shown that the final product of their decomposition both in the inert and reducing atmosphere is a powder consisting of bimetallic nanosized particles (nanoalloy) of Pd0.59Rh0.41 (Fm-3m space group, a = 3.856(2) Å, crystallite size of 8–11 nm).