New clathrates of Rb7.50(1)Tl0.50(1)Ge46 and K7.62(1)Tl0.38(1)Ge45.34(3)

Abstract

New Tl type-I clathrates of K_7.62(1)Tl_0.38(1)Ge_45.34(3) and Rb_7.50(1)Tl_0.50(1)Ge₄₆ were synthesized via solid-state reaction. Rb_7.50(1)Tl_0.50(1)Ge₄₆ and K_7.62(1)Tl_0.38(1)Ge_45.34(3) were found to crystallize in space groups Pmn and Iad with lattice parameters of a = 10.81559(7) Å and a = 21.4290(2) Å, respectively. Theoretical calculations indicated metallic features based on the calculation models of Rb₇Tl₁Ge₄₆ and K₇Tl₁Ge₄₆ in the space group of Pm. The densities of states at the Fermi level were predominantly determined by the Ge s and Ge p orbitals of Rb₇Tl₁Ge₄₆ and K₇Tl₁Ge₄₆.