Materials Data on NaCd4As3 by Materials Project

Abstract

NaCd4As3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Na1+ is bonded to six equivalent As3- atoms to form NaAs6 octahedra that share corners with twelve CdAs4 tetrahedra, edges with six equivalent NaAs6 octahedra, and edges with six equivalent CdAs4 tetrahedra. All Na–As bond lengths are 3.19 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 NaAs6 octahedra, corners with ten CdAs4 tetrahedra, edges with three equivalent NaAs6 octahedra, and edges with three equivalent CdAs4 tetrahedra. The corner-sharing octahedral tilt angles are 21°. There are three shorter (2.70 Å) and one longer (3.26 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 NaAs6 octahedra, corners with twelve CdAs4 tetrahedra, and edges with six CdAs4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are one shorter (2.71 Å) and three longer (2.87 Å) Cd–As bond lengths. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded to three equivalent Na1+ and four Cd2+ atoms to form a mixture of distorted edge and corner-sharing AsNa3Cd4 pentagonal bipyramids. In the second As3- site, As3- is bonded in a distorted body-centered cubic geometry to eight Cd2+ atoms.