Materials Data on Sr5NbN5 by Materials Project
Sr5NbN5 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to four N3- atoms to form distorted SrN4 trigonal pyramids that share corners with six equivalent SrN5 square pyramids, corners with two equivalent NbN4 tetrahedra, corners with two equivalent SrN5 trigonal bipyramids, corners with two equivalent SrN4 trigonal pyramids, and edges with four SrN5 trigonal bipyramids. There are two shorter (2.56 Å) and two longer (2.67 Å) Sr–N bond lengths. In the second Sr2+ site, Sr2+ is bonded to five N3- atoms to form distorted SrN5 trigonal bipyramids that share corners with two equivalent SrN5 square pyramids, corners with two equivalent NbN4 tetrahedra, corners with three equivalent SrN5 trigonal bipyramids, corners with two equivalent SrN4 trigonal pyramids, edges with two equivalent SrN5 square pyramids, an edgeedge with one NbN4 tetrahedra, edges with three SrN5 trigonal bipyramids, and edges with two equivalent SrN4 trigonal pyramids. There are a spread of Sr–N bond distances ranging from 2.53–2.75 Å. In the third Sr2+ site, Sr2+ is bonded to five N3- atoms to form SrN5 trigonal bipyramids that share corners with two equivalent SrN5 square pyramids, corners with four equivalent NbN4 tetrahedra, corners with three equivalent SrN5 trigonal bipyramids, edges with four equivalent SrN5 square pyramids, an edgeedge with one SrN5 trigonal bipyramid, and edges with two equivalent SrN4 trigonal pyramids. There are a spread of Sr–N bond distances ranging from 2.65–2.82 Å. In the fourth Sr2+ site, Sr2+ is bonded to five N3- atoms to form SrN5 square pyramids that share corners with two equivalent SrN5 square pyramids, corners with two equivalent NbN4 tetrahedra, corners with two SrN5 trigonal bipyramids, corners with three equivalent SrN4 trigonal pyramids, edges with three equivalent SrN5 square pyramids, an edgeedge with one NbN4 tetrahedra, and edges with three SrN5 trigonal bipyramids. There are a spread of Sr–N bond distances ranging from 2.63–2.72 Å. Nb5+ is bonded to four N3- atoms to form NbN4 tetrahedra that share corners with four equivalent SrN5 square pyramids, corners with six SrN5 trigonal bipyramids, corners with two equivalent SrN4 trigonal pyramids, edges with two equivalent SrN5 square pyramids, and an edgeedge with one SrN5 trigonal bipyramid. There are a spread of Nb–N bond distances ranging from 1.97–2.01 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded to five Sr2+ and one Nb5+ atom to form distorted NSr5Nb octahedra that share corners with four NSr6 octahedra, edges with six NSr6 octahedra, and a faceface with one NSr5Nb octahedra. The corner-sharing octahedra tilt angles range from 46–51°. In the second N3- site, N3- is bonded to six Sr2+ atoms to form NSr6 octahedra that share corners with nine NSr6 octahedra and edges with five NSr5Nb octahedra. The corner-sharing octahedra tilt angles range from 3–55°. In the third N3- site, N3- is bonded to five Sr2+ and one Nb5+ atom to form a mixture of distorted corner and edge-sharing NSr5Nb octahedra. The corner-sharing octahedra tilt angles range from 3–17°. In the fourth N3- site, N3- is bonded in a distorted rectangular see-saw-like geometry to three Sr2+ and one Nb5+ atom.