DOE OSTI2020
Ta3N5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 8-coordinate geometry to eight N3- atoms. There are a spread of Ta–N bond distances ranging from 2.06–2.31 Å. In the second Ta5+ site, Ta5+ is bonded in a 8-coordinate geometry to eight N3- atoms. There are a spread of Ta–N bond distances ranging from 2.05–2.28 Å. In the third Ta5+ site, Ta5+ is bonded in a 8-coordinate geometry to eight N3- atoms. There are a spread of Ta–N bond distances ranging from 2.08–2.25 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded in a 5-coordinate geometry to five Ta5+ atoms. In the second N3- site, N3- is bonded to four Ta5+ atoms to form distorted NTa4 tetrahedra that share corners with two equivalent NTa4 tetrahedra, corners with five equivalent NTa5 trigonal bipyramids, and an edgeedge with one NTa5 trigonal bipyramid. In the third N3- site, N3- is bonded in a 5-coordinate geometry to five Ta5+ atoms. In the fourth N3- site, N3- is bonded to five Ta5+ atoms to form distorted NTa5 trigonal bipyramids that share corners with five equivalent NTa4 tetrahedra, an edgeedge with one NTa4 tetrahedra, and edges with two equivalent NTa5 trigonal bipyramids. In the fifth N3- site, N3- is bonded in a 5-coordinate geometry to five Ta5+ atoms.