Materials Data on NaNbSe2O7 by Materials Project
NaNbO(SeO3)2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is two-dimensional and consists of two NaNbO(SeO3)2 sheets oriented in the (0, 1, 0) direction. Na1+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. There are two shorter (2.46 Å) and two longer (2.50 Å) Na–O bond lengths. Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Nb–O bond distances ranging from 1.83–2.17 Å. Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.67 Å) and two longer (1.78 Å) Se–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb5+ and one Se4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Nb5+ and one Se4+ atom. In the third O2- site, O2- is bonded in a trigonal non-coplanar geometry to two equivalent Na1+ and one Se4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Nb5+ atoms.