Materials Data on Na12NbO7 by Materials Project
Na12NbO7 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted T-shaped geometry to three equivalent O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.65 Å. In the second Na1+ site, Na1+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 2.27–2.38 Å. Nb2+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Nb–O bond lengths are 2.08 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Nb2+ atom to form distorted ONa5Nb octahedra that share corners with three equivalent ONa5Nb octahedra and edges with six ONa6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the second O2- site, O2- is bonded to six equivalent Na1+ atoms to form distorted edge-sharing ONa6 octahedra.