title: Ternary K2Zn5As4-type pnictides Rb2Cd5As4 and Rb2Zn5Sb4, and the solid solution Rb2Cd5(As,Sb)4.
abstract: Dirubidium pentacadmium tetraarsenide, Rb2Cd5As4, dirubidium pentazinc tetraantimonide, Rb2Zn5Sb4, and the solid-solution phase dirubidium pentacadmium tetra(arsenide/antimonide), Rb2Cd5(As,Sb)4 [or Rb2Cd5As3.00(1)Sb1.00(1)], have been prepared by direct reaction of the component elements at high temperature. These compounds are charge-balanced Zintl phases and adopt the orthorhombic K2Zn5As4-type structure (Pearson symbol oC44), featuring a three-dimensional [M5Pn4](2-) framework [M = Zn or Cd; Pn is a pnicogen or Group 15 (Group V) element] built of linked MPn4 tetrahedra, and large channels extending along the b axis which host Rb(+) cations. The As and Sb atoms in Rb2Cd5(As,Sb)4 are randomly disordered over the two available pnicogen sites. Band-structure calculations predict that Rb2Cd5As4 is a small-band-gap semiconductor and Rb2Zn5Sb4 is a semimetal.
authors: Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
authors: Hua
authors: H
authors: He
authors: Stanislav S
authors: SS
authors: Stoyko
authors: Arthur
authors: A
authors: Mar
authors: Svilen
authors: S
authors: Bobev