DOI: 10.17188/1738819
title: Materials Data on Na9Sm(GeSe3)4 by Materials Project

description: Na9Sm(Ge2Se6)2 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share a cornercorner with one SmSe6 octahedra, corners with three NaSe6 octahedra, an edgeedge with one SmSe6 octahedra, and edges with nine NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 3–9°. There are a spread of Na–Se bond distances ranging from 3.03–3.26 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share a cornercorner with one SmSe6 octahedra, corners with three NaSe6 octahedra, an edgeedge with one SmSe6 octahedra, and edges with nine NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 3–13°. There are a spread of Na–Se bond distances ranging from 3.01–3.29 Å. In the third Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share a cornercorner with one SmSe6 octahedra, corners with three NaSe6 octahedra, an edgeedge with one SmSe6 octahedra, and edges with nine NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Na–Se bond distances ranging from 2.95–3.18 Å. In the fourth Na1+ site, Na1+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are two shorter (3.07 Å) and four longer (3.10 Å) Na–Se bond lengths. In the fifth Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with six NaSe6 octahedra, an edgeedge with one SmSe6 octahedra, and edges with eight NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–13°. There are a spread of Na–Se bond distances ranging from 3.06–3.14 Å. In the sixth Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with six NaSe6 octahedra, edges with two equivalent SmSe6 octahedra, and edges with seven NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 3–7°. There are a spread of Na–Se bond distances ranging from 3.04–3.11 Å. Sm3+ is bonded to six Se2- atoms to form SmSe6 octahedra that share corners with six NaSe6 octahedra and edges with nine NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Sm–Se bond distances ranging from 2.95–2.98 Å. There are two inequivalent Ge3+ sites. In the first Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of Ge–Se bond distances ranging from 2.37–2.46 Å. In the second Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.36 Å) and two longer (2.41 Å) Ge–Se bond lengths. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four Na1+, one Sm3+, and one Ge3+ atom to form SeNa4SmGe octahedra that share corners with seven SeNa4SmGe octahedra and edges with ten SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 4–87°. In the second Se2- site, Se2- is bonded to five Na1+ and one Ge3+ atom to form a mixture of corner and edge-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 2–86°. In the third Se2- site, Se2- is bonded to five Na1+ and one Ge3+ atom to form SeNa5Ge octahedra that share corners with seven SeNa5Ge octahedra and edges with ten SeNa4SmGe octahedra. The corner-sharing octahedra tilt angles range from 2–85°. In the fourth Se2- site, Se2- is bonded to four Na1+, one Sm3+, and one Ge3+ atom to form a mixture of corner and edge-sharing SeNa4SmGe octahedra. The corner-sharing octahedra tilt angles range from 3–87°. In the fifth Se2- site, Se2- is bonded to five Na1+ and one Ge3+ atom to form a mixture of corner and edge-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 2–87°. In the sixth Se2- site, Se2- is bonded to four Na1+, one Sm3+, and one Ge3+ atom to form a mixture of corner and edge-sharing SeNa4SmGe octahedra. The corner-sharing octahedra tilt angles range from 2–87°.