Materials Data on NaSm2Se3 by Materials Project
NaSm2Se3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c 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 SmSe6 octahedra, edges with two equivalent NaSe6 octahedra, and edges with ten SmSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (2.96 Å) and four longer (2.98 Å) Na–Se bond lengths. There are two inequivalent Sm+2.50+ sites. In the first Sm+2.50+ site, Sm+2.50+ is bonded to six Se2- atoms to form SmSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four SmSe6 octahedra, edges with five equivalent NaSe6 octahedra, and edges with seven SmSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Sm–Se bond distances ranging from 2.94–2.97 Å. In the second Sm+2.50+ site, Sm+2.50+ is bonded to six Se2- atoms to form SmSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four SmSe6 octahedra, edges with five equivalent NaSe6 octahedra, and edges with seven SmSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Sm–Se bond distances ranging from 2.95–2.97 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Na1+ and four Sm+2.50+ atoms to form a mixture of corner and edge-sharing SeNa2Sm4 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 Sm+2.50+ atoms to form a mixture of corner and edge-sharing SeNa2Sm4 octahedra. The corner-sharing octahedral tilt angles are 0°.