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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Na(Nd2Se3)4 by Materials Project

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°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaNdSe2 by Materials Project

NaNdSe2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Na1+ is bonded to six equivalent Se2- atoms to form NaSe6 octahedra that share corners with six equivalent NdSe6 octahedra, edges with six equivalent NaSe6 octahedra, and edges with six equivalent NdSe6 octahedra. The corner-sharing octahedral tilt angles are 3°. All Na–Se bond lengths are 3.10 Å. Nd3+ is bonded to six equivalent Se2- atoms to form NdSe6 octahedra that share corners with six equivalent NaSe6 octahedra, edges with six equivalent NaSe6 octahedra, and edges with six equivalent NdSe6 octahedra. The corner-sharing octahedral tilt angles are 3°. All Nd–Se bond lengths are 2.98 Å. Se2- is bonded to three equivalent Na1+ and three equivalent Nd3+ atoms to form a mixture of edge and corner-sharing SeNa3Nd3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaNd2Se3 by Materials Project

NaNd2Se3 is Caswellsilverite-like structured and crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four equivalent NdSe6 octahedra, edges with two equivalent NaSe6 octahedra, and edges with ten equivalent NdSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (3.00 Å) and four longer (3.01 Å) Na–Se bond lengths. Nd+2.50+ is bonded to six Se2- atoms to form NdSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four equivalent NdSe6 octahedra, edges with five equivalent NaSe6 octahedra, and edges with seven equivalent NdSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Nd–Se bond distances ranging from 2.98–3.02 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Na1+ and four equivalent Nd+2.50+ atoms to form a mixture of edge and corner-sharing SeNa2Nd4 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second Se2- site, Se2- is bonded to two equivalent Na1+ and four equivalent Nd+2.50+ atoms to form a mixture of edge and corner-sharing SeNa2Nd4 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.

36 MATERIALS SCIENCE↗