Palladium sulfide bronzes, MPd3S4 (M = La, Nd, En, Gd, Dy, Yb) were synthesised in a single phase by the reaction of rare-earth sesquisulfide, palladium powder, and sulfur in sealed quartz tubes under vacuum at 1173 K for 3 d. These bronzes were cubic with space group Pm3?. The lattice parameter of MPd3S4 was found to exhibit a monotonic increase with increasing crystal radius of M3+ in an eight-coordination of sulfur atoms except for Eu and Yb. The specific resistivity of MPd3S4 increased with increasing temperature, from 15 to 300 K, showing that* these bronzes are metallic conductors. The carrier of MPd3S4 (M = La., Nd, Eu) is negatively charged as obtained from the Hall effect measurements. The Hall coefficients of these bronzes gave no significant change with temperature from 50 to 293 K. The numbers of electrons per unit cell for LaPd3S4) NdPd3S4 and EuPd3S4 were 1.71, 1.68 and 0.82, respectively, in good agreement with the theoretical values.
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