Materials Data on Na(Nd2Se3)4 by Materials Project

Abstract

Na(Nd2Se3)4 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Na1+ is bonded to eight Se2- atoms to form distorted NaSe8 hexagonal bipyramids that share corners with eight equivalent NdSe8 hexagonal bipyramids, edges with four equivalent NdSe8 hexagonal bipyramids, and faces with eight NdSe8 hexagonal bipyramids. There are four shorter (3.03 Å) and four longer (3.27 Å) Na–Se bond lengths. There are three inequivalent Nd+2.88+ sites. In the first Nd+2.88+ site, Nd+2.88+ is bonded to eight Se2- atoms to form distorted NdSe8 hexagonal bipyramids that share corners with two equivalent NaSe8 hexagonal bipyramids, corners with six NdSe8 hexagonal bipyramids, edges with four NdSe8 hexagonal bipyramids, a faceface with one NaSe8 hexagonal bipyramid, and faces with seven NdSe8 hexagonal bipyramids. There are a spread of Nd–Se bond distances ranging from 2.97–3.23 Å. In the second Nd+2.88+ site, Nd+2.88+ is bonded to eight Se2- atoms to form distorted NdSe8 hexagonal bipyramids that share corners with eight NdSe8 hexagonal bipyramids, edges with four NdSe8 hexagonal bipyramids, faces with two equivalent NaSe8 hexagonal bipyramids, and faces with six NdSe8 hexagonal bipyramids. There are a spread of Nd–Se bond distances ranging from 3.00–3.23 Å. In the third Nd+2.88+ site, Nd+2.88+ is bonded to eight Se2- atoms to form distorted NdSe8 hexagonal bipyramids that share corners with eight NdSe8 hexagonal bipyramids, edges with two equivalent NaSe8 hexagonal bipyramids, edges with two equivalent NdSe8 hexagonal bipyramids, and faces with eight NdSe8 hexagonal bipyramids. There are a spread of Nd–Se bond distances ranging from 2.99–3.21 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Na1+ and five Nd+2.88+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNaNd5 octahedra. The corner-sharing octahedra tilt angles range from 14–52°. In the second Se2- site, Se2- is bonded to one Na1+ and five Nd+2.88+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNaNd5 octahedra. The corner-sharing octahedra tilt angles range from 19–50°. In the third Se2- site, Se2- is bonded to six Nd+2.88+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNd6 octahedra. The corner-sharing octahedra tilt angles range from 16–52°.