Materials Data on Na2Nb4Se4O19 by Materials Project
Na2Nb4Se4O19 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.39–2.89 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 4–7°. There are a spread of Nb–O bond distances ranging from 1.83–2.19 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Nb–O bond distances ranging from 1.84–2.19 Å. There are two inequivalent Se4+ sites. In the first Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.73 Å) and one longer (1.75 Å) Se–O bond length. In the second Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.68–1.79 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Nb5+ and one Se4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Nb5+, and one Se4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Nb5+, and one Se4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Nb5+ and one Se4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb5+ and one Se4+ atom. In the sixth O2- site, O2- is bonded to three equivalent Na1+ and one Se4+ atom to form a mixture of distorted edge and corner-sharing ONa3Se tetrahedra. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two Nb5+ atoms. In the ninth O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms.