Materials Data on La(ZnAs)3 by Materials Project
La(ZnAs)3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. La3+ is bonded to seven As3- atoms to form distorted LaAs7 pentagonal bipyramids that share corners with thirteen ZnAs4 tetrahedra, edges with two equivalent LaAs7 pentagonal bipyramids, edges with seven ZnAs4 tetrahedra, and faces with two equivalent LaAs7 pentagonal bipyramids. There are a spread of La–As bond distances ranging from 3.06–3.23 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 four equivalent LaAs7 pentagonal bipyramids, corners with nine ZnAs4 tetrahedra, edges with three equivalent LaAs7 pentagonal bipyramids, and an edgeedge with one ZnAs4 tetrahedra. There are a spread of Zn–As bond distances ranging from 2.52–2.58 Å. In the second Zn2+ site, Zn2+ is bonded to four As3- atoms to form ZnAs4 tetrahedra that share corners with three equivalent LaAs7 pentagonal bipyramids, corners with eight ZnAs4 tetrahedra, edges with three equivalent LaAs7 pentagonal bipyramids, and edges with two equivalent ZnAs4 tetrahedra. There are a spread of Zn–As bond distances ranging from 2.49–2.80 Å. In the third Zn2+ site, Zn2+ is bonded to four As3- atoms to form ZnAs4 tetrahedra that share corners with six equivalent LaAs7 pentagonal bipyramids, corners with five ZnAs4 tetrahedra, an edgeedge with one LaAs7 pentagonal bipyramid, and edges with five ZnAs4 tetrahedra. There are three shorter (2.58 Å) and one longer (2.63 Å) Zn–As bond lengths. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 7-coordinate geometry to two equivalent La3+ and five Zn2+ atoms. In the second As3- site, As3- is bonded in a 6-coordinate geometry to two equivalent La3+ and four Zn2+ atoms. In the third As3- site, As3- is bonded to three equivalent La3+ and three Zn2+ atoms to form distorted edge-sharing AsLa3Zn3 octahedra.