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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Na(Pr2Se3)4 by Materials Project

Na(Pr2Se3)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 PrSe8 hexagonal bipyramids, edges with four equivalent PrSe8 hexagonal bipyramids, and faces with eight PrSe8 hexagonal bipyramids. There are four shorter (3.05 Å) and four longer (3.29 Å) Na–Se bond lengths. There are three inequivalent Pr sites. In the first Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent NaSe8 hexagonal bipyramids, corners with six PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, a faceface with one NaSe8 hexagonal bipyramid, and faces with seven PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.00–3.25 Å. In the second Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with eight PrSe8 hexagonal bipyramids, edges with two equivalent NaSe8 hexagonal bipyramids, edges with two equivalent PrSe8 hexagonal bipyramids, and faces with eight PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.01–3.22 Å. In the third Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with eight PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, faces with two equivalent NaSe8 hexagonal bipyramids, and faces with six PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.03–3.25 Å. There are three inequivalent Se sites. In the first Se site, Se is bonded to one Na and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeNaPr5 octahedra. The corner-sharing octahedra tilt angles range from 14–52°. In the second Se site, Se is bonded to one Na and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeNaPr5 octahedra. The corner-sharing octahedra tilt angles range from 19–50°. In the third Se site, Se is bonded to six Pr atoms to form a mixture of distorted edge, face, and corner-sharing SePr6 octahedra. The corner-sharing octahedra tilt angles range from 16–52°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaPrSe2 by Materials Project

NaPrSe2 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 PrSe6 octahedra, edges with six equivalent NaSe6 octahedra, and edges with six equivalent PrSe6 octahedra. The corner-sharing octahedral tilt angles are 3°. All Na–Se bond lengths are 3.10 Å. Pr3+ is bonded to six equivalent Se2- atoms to form PrSe6 octahedra that share corners with six equivalent NaSe6 octahedra, edges with six equivalent NaSe6 octahedra, and edges with six equivalent PrSe6 octahedra. The corner-sharing octahedral tilt angles are 3°. All Pr–Se bond lengths are 3.00 Å. Se2- is bonded to three equivalent Na1+ and three equivalent Pr3+ atoms to form a mixture of corner and edge-sharing SeNa3Pr3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaPr2Se3 by Materials Project

NaPr2Se3 is Caswellsilverite-like structured and crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Na is bonded to six Se atoms to form NaSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four equivalent PrSe6 octahedra, edges with two equivalent NaSe6 octahedra, and edges with ten equivalent PrSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Na–Se bond lengths are 3.02 Å. Pr is bonded to six Se atoms to form PrSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four equivalent PrSe6 octahedra, edges with five equivalent NaSe6 octahedra, and edges with seven equivalent PrSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Pr–Se bond distances ranging from 3.00–3.05 Å. There are two inequivalent Se sites. In the first Se site, Se is bonded to two equivalent Na and four equivalent Pr atoms to form a mixture of edge and corner-sharing SeNa2Pr4 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second Se site, Se is bonded to two equivalent Na and four equivalent Pr atoms to form a mixture of edge and corner-sharing SeNa2Pr4 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.

36 MATERIALS SCIENCE↗