The new compounds KCuZrQ3 (Q = S, Se, Te) and KCuHfS3 have been synthesized through direct reaction of the elements with a K2Qy flux. The compounds crystallize in space group D172h-Cmcm of the orthorhombic system with four formula units in cells of dimensions: a = 3.730(2), b = 13.915(7), and c = 9.754(6)Å for KCuZrS3; a = 3.874(2), b = 14.506 (7), and c = 10.159(5)Å for KCuZrSe3; and a = 4.088(1), b = 15.299(5), and c = 10.886(3)Å for KCuZrTe3 (T = 113 K). From photographs taken at room temperature the cell parameters for KCuHfS3 are a = 3.70(6), b = 14.24(2), and c = 9.86(5)Å. The structures of the KCuZrQ3 compounds have been determined from single-crystal X-ray methods. The KCuZrQ3 structure is composed of 2∞[CuZrQ-3] layers separated by K+ cations that are coordinated by eight atoms in a bicapped trigonal prismatic arrangement. The Cu atoms are tetrahedrally coordinated and the Zr atoms are octahedrally coordinated by Q atoms. Within the 2∞[CuZrQ-3] layer, the tetrahedra share edges with four adjacent octahedra. The crystal structure is related to FeUS3 or its structural anti-type Pd3Te2, with Cu atoms occupying the tetrahedral sites that remain unoccupied in the parent structures. Electrical conductivity measurements indicate that KCuZrS3 is an insulator; KCuZrSe3 undergoes a metal-to-semiconductor transition at 50 K; and KCuZrTe3 is a metal.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry