Materials Data on Na2Zn3GeAs4 by Materials Project

Abstract

Na2Zn3GeAs4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six As3- atoms to form NaAs6 octahedra that share corners with five equivalent GeAs4 tetrahedra, corners with seven ZnAs4 tetrahedra, edges with six NaAs6 octahedra, an edgeedge with one GeAs4 tetrahedra, and edges with five ZnAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 2.95–3.19 Å. In the second Na1+ site, Na1+ is bonded to six As3- atoms to form NaAs6 octahedra that share a cornercorner with one GeAs4 tetrahedra, corners with eleven ZnAs4 tetrahedra, edges with six NaAs6 octahedra, edges with two equivalent GeAs4 tetrahedra, and edges with four ZnAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 3.04–3.24 Å. There are three inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four As3- atoms to form ZnAs4 tetrahedra that share corners with six NaAs6 octahedra, corners with two equivalent ZnAs4 tetrahedra, corners with four equivalent GeAs4 tetrahedra, edges with three NaAs6 octahedra, and edges with three ZnAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 17–54°. There are two shorter (2.54 Å) and two longer (2.63 Å) Zn–As bond lengths. In the second Zn2+ site, Zn2+ is bonded to four As3- atoms to form distorted ZnAs4 tetrahedra that share corners with six NaAs6 octahedra, corners with six ZnAs4 tetrahedra, edges with three NaAs6 octahedra, an edgeedge with one ZnAs4 tetrahedra, and edges with two equivalent GeAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–49°. There are a spread of Zn–As bond distances ranging from 2.42–2.93 Å. In the third Zn2+ site, Zn2+ is bonded to four As3- atoms to form ZnAs4 tetrahedra that share corners with six NaAs6 octahedra, corners with six ZnAs4 tetrahedra, edges with three NaAs6 octahedra, an edgeedge with one GeAs4 tetrahedra, and edges with two equivalent ZnAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–50°. There are a spread of Zn–As bond distances ranging from 2.45–2.85 Å. Ge4+ is bonded to four As3- atoms to form GeAs4 tetrahedra that share corners with six NaAs6 octahedra, corners with two equivalent GeAs4 tetrahedra, corners with four equivalent ZnAs4 tetrahedra, edges with three NaAs6 octahedra, and edges with three ZnAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–49°. There are a spread of Ge–As bond distances ranging from 2.50–2.58 Å. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded to three Na1+ and four Zn2+ atoms to form distorted edge-sharing AsNa3Zn4 pentagonal bipyramids. In the second As3- site, As3- is bonded in a 7-coordinate geometry to three Na1+, three Zn2+, and one Ge4+ atom. In the third As3- site, As3- is bonded in a 7-coordinate geometry to three Na1+, three Zn2+, and one Ge4+ atom. In the fourth As3- site, As3- is bonded in a 7-coordinate geometry to three Na1+, two Zn2+, and two equivalent Ge4+ atoms.