Interpenetrating icosahedra chains based zinc-rich ternary phases Ru _(4.0)Sn_(2.9)Zn_(11.6) and Ru_(3.0)Sb _(0.97)Zn_(11.0): Synthesis, structures and physical properties

摘要

Substituting of Ru with Sn and Sb in the phase RuZn_3 led to two new zinc-rich ternary compounds: Ru_4Sn_(2.9)Zn_(11.6) (SnRZ: Monoclinic, C2/m, Pearson symbol oC46-δ, a = 6.8011(14), b = 7.9760(16), c = 11.083(2) ?, β = 97.56(3)°, Z = 2) and Ru _(3.0)Sb_(0.97)Zn_(11.0) (SbRZ: Orthorhombic, Cmcm, Pearson symbol oC60, a = 7.8936(16), b = 6.8347(14), c = 16.904(3) ?, Z = 4). The structures of SnRZ and SbRZ are composed of four identical atomic layers but with different stacking sequences. They exhibit structural units of either three or two interpenetrating icosahedra fusing to form chains along the c axis. Their a and b lattice parameters are alike - interchanged in the chosen conventional setting - while the c parameters are related by c_(SbRZ)/2 × (1 + τ) ≈ 2c_(SnRZ) with τ = (1 + √5)/2 being the golden mean (known as τ-inflated phases). Both two compounds exhibit diamagnetic properties, and SnRZ and SbRZ congruently melt at 1296 K and 1233 K, respectively. Temperature-dependent resistivities reveal metallic behavior. The negative Seebeck coefficients indicate transport processes are dominated by electrons as carriers.