DOE OSTI2020
Na3NbS4 crystallizes in the orthorhombic Fdd2 space group. The structure is three-dimensional. there are seven inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five S2- atoms. There are a spread of Na–S bond distances ranging from 2.92–3.25 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Na–S bond distances ranging from 2.96–3.51 Å. In the third Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with six NaS6 octahedra, corners with four NbS4 tetrahedra, edges with two NaS6 octahedra, an edgeedge with one NbS4 tetrahedra, and a faceface with one NaS6 octahedra. The corner-sharing octahedra tilt angles range from 30–59°. There are a spread of Na–S bond distances ranging from 2.85–3.02 Å. In the fourth Na1+ site, Na1+ is bonded to six S2- atoms to form distorted NaS6 octahedra that share corners with two equivalent NaS6 octahedra, corners with four NbS4 tetrahedra, edges with four NaS6 octahedra, an edgeedge with one NbS4 tetrahedra, and a faceface with one NaS6 octahedra. The corner-sharing octahedra tilt angles range from 30–59°. There are a spread of Na–S bond distances ranging from 2.82–3.25 Å. In the fifth Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with four equivalent NaS6 octahedra, corners with four NbS4 tetrahedra, edges with four NaS6 octahedra, and an edgeedge with one NbS4 tetrahedra. The corner-sharing octahedra tilt angles range from 32–39°. There are a spread of Na–S bond distances ranging from 2.87–3.01 Å. In the sixth Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with two equivalent NbS4 tetrahedra, edges with six NaS6 octahedra, and edges with two equivalent NbS4 tetrahedra. There are a spread of Na–S bond distances ranging from 2.91–3.29 Å. In the seventh Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with two equivalent NbS4 tetrahedra, edges with six NaS6 octahedra, and edges with two equivalent NbS4 tetrahedra. There are a spread of Na–S bond distances ranging from 2.90–3.28 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to four S2- atoms to form NbS4 tetrahedra that share corners with seven NaS6 octahedra and edges with two NaS6 octahedra. The corner-sharing octahedra tilt angles range from 10–75°. There are a spread of Nb–S bond distances ranging from 2.28–2.30 Å. In the second Nb5+ site, Nb5+ is bonded to four S2- atoms to form NbS4 tetrahedra that share corners with seven NaS6 octahedra and edges with three NaS6 octahedra. The corner-sharing octahedra tilt angles range from 9–77°. There are two shorter (2.29 Å) and two longer (2.30 Å) Nb–S bond lengths. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to four Na1+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing SNa4Nb trigonal bipyramids. In the second S2- site, S2- is bonded in a 6-coordinate geometry to five Na1+ and one Nb5+ atom. In the third S2- site, S2- is bonded in a 6-coordinate geometry to five Na1+ and one Nb5+ atom. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to five Na1+ and one Nb5+ atom. In the fifth S2- site, S2- is bonded to four Na1+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing SNa4Nb square pyramids. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to four Na1+ and one Nb5+ atom. In the seventh S2- site, S2- is bonded in a 5-coordinate geometry to four Na1+ and one Nb5+ atom. In the eighth S2- site, S2- is bonded to four Na1+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing SNa4Nb square pyramids.