Materials Data on KCd4As3 by Materials Project

Abstract

KCd4As3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. K1+ is bonded to six equivalent As3- atoms to form KAs6 octahedra that share corners with twelve CdAs4 tetrahedra, edges with six equivalent KAs6 octahedra, and edges with six equivalent CdAs4 tetrahedra. All K–As bond lengths are 3.45 Å. There are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to four As3- atoms to form distorted CdAs4 tetrahedra that share corners with three equivalent KAs6 octahedra, corners with ten CdAs4 tetrahedra, edges with three equivalent KAs6 octahedra, and edges with three equivalent CdAs4 tetrahedra. The corner-sharing octahedral tilt angles are 27°. There are three shorter (2.71 Å) and one longer (3.25 Å) Cd–As bond lengths. In the second Cd2+ site, Cd2+ is bonded to four As3- atoms to form CdAs4 tetrahedra that share corners with three equivalent KAs6 octahedra, corners with twelve CdAs4 tetrahedra, and edges with six CdAs4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are one shorter (2.71 Å) and three longer (2.88 Å) Cd–As bond lengths. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 7-coordinate geometry to three equivalent K1+ and four Cd2+ atoms. In the second As3- site, As3- is bonded in a distorted body-centered cubic geometry to eight Cd2+ atoms.