Materials Data on Na(Ce2Se3)4 by Materials Project
Na(Ce2Se3)4 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Na is bonded to eight Se atoms to form distorted NaSe8 hexagonal bipyramids that share corners with eight equivalent CeSe8 hexagonal bipyramids, edges with four equivalent CeSe8 hexagonal bipyramids, and faces with eight CeSe8 hexagonal bipyramids. There are four shorter (3.03 Å) and four longer (3.27 Å) Na–Se bond lengths. There are three inequivalent Ce sites. In the first Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share corners with two equivalent NaSe8 hexagonal bipyramids, corners with six CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, a faceface with one NaSe8 hexagonal bipyramid, and faces with seven CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.98–3.22 Å. In the second Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share corners with eight CeSe8 hexagonal bipyramids, edges with two equivalent NaSe8 hexagonal bipyramids, edges with two equivalent CeSe8 hexagonal bipyramids, and faces with eight CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.98–3.17 Å. In the third Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share corners with eight CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, faces with two equivalent NaSe8 hexagonal bipyramids, and faces with six CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 3.01–3.20 Å. There are three inequivalent Se sites. In the first Se site, Se is bonded to six Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCe6 octahedra. The corner-sharing octahedra tilt angles range from 15–51°. In the second Se site, Se is bonded to one Na and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeNaCe5 octahedra. The corner-sharing octahedra tilt angles range from 19–50°. In the third Se site, Se is bonded to one Na and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeNaCe5 octahedra. The corner-sharing octahedra tilt angles range from 15–51°.