DOE OSTI2020
NaV2O4 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.40 Å) and four longer (2.52 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.43 Å) and four longer (2.56 Å) Na–O bond lengths. There are two inequivalent V+3.50+ sites. In the first V+3.50+ site, V+3.50+ is bonded to six O2- atoms to form edge-sharing VO6 octahedra. There are a spread of V–O bond distances ranging from 1.88–2.04 Å. In the second V+3.50+ site, V+3.50+ is bonded to six O2- atoms to form edge-sharing VO6 octahedra. There are a spread of V–O bond distances ranging from 2.03–2.06 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two Na1+ and three V+3.50+ atoms to form ONa2V3 trigonal bipyramids that share corners with five equivalent ONa2V3 trigonal bipyramids, corners with two equivalent ONaV3 trigonal pyramids, edges with four equivalent ONa2V3 trigonal bipyramids, and edges with two equivalent ONaV3 trigonal pyramids. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+ and three V+3.50+ atoms. In the third O2- site, O2- is bonded to one Na1+ and three V+3.50+ atoms to form distorted ONaV3 trigonal pyramids that share corners with four equivalent ONa2V3 trigonal bipyramids, corners with three equivalent ONaV3 trigonal pyramids, and edges with four equivalent ONa2V3 trigonal bipyramids.