Crystal structure and physical properties of the new ternary antimonides Ln3Pd8Sb4 (Ln=Y, Gd, Tb, Dy, Ho, Er, Tm)

The ternary antimonides Ln3Pd8Sb4 (Ln=Y, Gd, Tb, Dy, Ho, Er, Tm) have been synthesized for the first time. The crystal structure of Er3Pd8Sb4 has been solved from the X-ray single crystal data: own type structure, space group Fm3¯m, a=1.3050(1) nm, RF=0.0484, RW=0.0524 for 17 free parameters and 401 reflections with F(hkl)>4σ(F). The structure of Er3Pd8Sb4 can be viewed as a ternary ordered version of the Sc11Ir4-type. The lattice parameters of the isotypic compounds Ln3Pd8Sb4 (Ln=Y, Gd, Tb, Dy, Ho, Tm) have been refined from the X-ray powder diffraction data. The magnetic and electrical properties of the compounds Ln3Pd8Sb4 (Ln=Tb, Ho, Er) have been studied down to 1.75 K. The Ho- and Er-based phases have been found to order antiferromagnetically at 2.5 and 2.0 K, respectively. For all three compounds, the magnetic susceptibility follows in the paramagnetic region the Curie–Weiss behavior with the effective magnetic moments close to the respective free trivalent ion values. All three antimonides studied exhibit metallic character of the electrical conductivity.