Crystal structure and magnetic susceptibility of uranium palladium sulfide bronze, U_xPd₃S₄

The lattice parameter of cubic U_xPd₃S₄ was measured by X-ray diffractometry for various apparent x values between 0.5 and 1.5. It seemed to change with x, but the existence of a non-stoichiometric range for uranium could not be definitely determined since the product was not in a single phase. The Rietveld refinement for U_xPd₃S₄ (x = 1) showed that the compound was U_0.90Pd₃S₄ and that the space group was Pm3n with the final R_I value of 0.052. The lattice parameter was 6.637(1) Å, and the isotropic temperature factors were 0.59, 0.70 and 0.70 Ų for U, Pd and S, respectively. The measured reciprocal magnetic susceptibility for U_0.90Pd₃S₄ was not a linear function of temperature. From the slope in a temperature range of 50-200 K, the effective magnetic moment was obtained, which showed that both the U⁴⁺ and U³⁺ ions are present in this compound in nearly the same amounts.