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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaNbSe2 by Materials Project

NaNbSe2 is Tungsten Carbide-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Na1+ is bonded to six equivalent Se2- atoms to form distorted NaSe6 octahedra that share corners with twelve equivalent NbSe6 pentagonal pyramids, edges with six equivalent NaSe6 octahedra, and faces with two equivalent NbSe6 pentagonal pyramids. All Na–Se bond lengths are 2.95 Å. Nb3+ is bonded to six equivalent Se2- atoms to form distorted NbSe6 pentagonal pyramids that share corners with twelve equivalent NaSe6 octahedra, edges with six equivalent NbSe6 pentagonal pyramids, and faces with two equivalent NaSe6 octahedra. The corner-sharing octahedral tilt angles are 44°. All Nb–Se bond lengths are 2.65 Å. Se2- is bonded to three equivalent Na1+ and three equivalent Nb3+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNa3Nb3 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na(NbSe2)2 by Materials Project

Na(NbSe2)2 crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one Na(NbSe2)2 sheet oriented in the (0, 0, 1) direction. Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are three shorter (2.96 Å) and three longer (2.97 Å) Na–Se bond lengths. There are two inequivalent Nb+3.50+ sites. In the first Nb+3.50+ site, Nb+3.50+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are three shorter (2.62 Å) and three longer (2.65 Å) Nb–Se bond lengths. In the second Nb+3.50+ site, Nb+3.50+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are three shorter (2.62 Å) and three longer (2.65 Å) Nb–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.50+ atoms to form a mixture of distorted edge, face, and corner-sharing SeNa3Nb3 octahedra. In the second Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.50+ atoms to form a mixture of distorted edge, face, and corner-sharing SeNa3Nb3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 40°. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.50+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2(NbSe2)3 by Materials Project

Na3(NbSe2)4Na(NbSe2)2 crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one Na(NbSe2)2 sheet oriented in the (0, 0, 1) direction and one Na3(NbSe2)4 sheet oriented in the (0, 0, 1) direction. In the Na(NbSe2)2 sheet, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. All Na–Se bond lengths are 2.96 Å. There are two inequivalent Nb+3.33+ sites. In the first Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are three shorter (2.62 Å) and three longer (2.65 Å) Nb–Se bond lengths. In the second Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are three shorter (2.62 Å) and three longer (2.65 Å) Nb–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNa3Nb3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 41°. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.33+ atoms. In the third Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of corner, edge, and face-sharing SeNa3Nb3 octahedra. All Se–Nb bond lengths are 2.65 Å. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.33+ atoms. All Se–Nb bond lengths are 2.62 Å. In the Na3(NbSe2)4 sheet, there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. All Na–Se bond lengths are 2.96 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are three shorter (2.95 Å) and three longer (2.96 Å) Na–Se bond lengths. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. All Na–Se bond lengths are 2.96 Å. There are four inequivalent Nb+3.33+ sites. In the first Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. All Nb–Se bond lengths are 2.64 Å. In the second Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are three shorter (2.62 Å) and three longer (2.65 Å) Nb–Se bond lengths. In the third Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. All Nb–Se bond lengths are 2.64 Å. In the fourth Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNa3Nb3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 41°. In the second Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNa3Nb3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 41°. In the third Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNa3Nb3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 41°. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.33+ atoms. In the fifth Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of corner, edge, and face-sharing SeNa3Nb3 octahedra. The corner-sharing octahedral tilt angles are 46°. In the sixth Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of corner, edge, and face-sharing SeNa3Nb3 octahedra. In the seventh Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Nb+3.33+ atoms to form a mixture of corner, edge, and face-sharing SeNa3Nb3 octahedra. The corner-sharing octahedral tilt angles are 46°. In the eighth Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na(Nb3Se4)2 by Materials Project

Na(Nb3Se4)2 crystallizes in the trigonal P-3 space group. The structure is three-dimensional. Na1+ is bonded in a distorted hexagonal planar geometry to six equivalent Se2- atoms. All Na–Se bond lengths are 3.28 Å. Nb+2.50+ is bonded to six Se2- atoms to form a mixture of distorted face, edge, and corner-sharing NbSe6 octahedra. The corner-sharing octahedra tilt angles range from 45–55°. There are a spread of Nb–Se bond distances ranging from 2.61–2.82 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six equivalent Nb+2.50+ atoms to form distorted face-sharing SeNb6 pentagonal pyramids. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one Na1+ and four equivalent Nb+2.50+ atoms.

36 MATERIALS SCIENCE↗