Materials Data on Ca5NbN5 by Materials Project

Abstract

Ca5NbN5 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are seven inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to five N3- atoms to form CaN5 trigonal bipyramids that share corners with three equivalent CaN5 square pyramids, corners with three NbN4 tetrahedra, a cornercorner with one CaN4 trigonal pyramid, an edgeedge with one CaN6 octahedra, edges with two CaN5 square pyramids, and edges with four CaN5 trigonal bipyramids. There are a spread of Ca–N bond distances ranging from 2.49–2.65 Å. In the second Ca2+ site, Ca2+ is bonded to five N3- atoms to form CaN5 trigonal bipyramids that share corners with three equivalent CaN6 octahedra, corners with three NbN4 tetrahedra, a cornercorner with one CaN4 trigonal pyramid, edges with three CaN5 square pyramids, and edges with four equivalent CaN5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 5–10°. There are a spread of Ca–N bond distances ranging from 2.49–2.54 Å. In the third Ca2+ site, Ca2+ is bonded to five N3- atoms to form CaN5 square pyramids that share corners with two equivalent CaN5 square pyramids, corners with three equivalent NbN4 tetrahedra, corners with two equivalent CaN4 trigonal pyramids, edges with two equivalent CaN6 octahedra, edges with two equivalent CaN5 square pyramids, an edgeedge with one NbN4 tetrahedra, and edges with three CaN5 trigonal bipyramids. There are one shorter (2.53 Å) and four longer (2.55 Å) Ca–N bond lengths. In the fourth Ca2+ site, Ca2+ is bonded to five N3- atoms to form CaN5 square pyramids that share corners with two CaN5 square pyramids, corners with three equivalent CaN5 trigonal bipyramids, a cornercorner with one CaN4 trigonal pyramid, edges with two equivalent CaN6 octahedra, edges with two CaN5 square pyramids, edges with two NbN4 tetrahedra, and edges with two CaN5 trigonal bipyramids. There are a spread of Ca–N bond distances ranging from 2.32–2.61 Å. In the fifth Ca2+ site, Ca2+ is bonded in a distorted rectangular see-saw-like geometry to four N3- atoms. There are a spread of Ca–N bond distances ranging from 2.39–2.50 Å. In the sixth Ca2+ site, Ca2+ is bonded to six N3- atoms to form CaN6 octahedra that share corners with three equivalent NbN4 tetrahedra, corners with three equivalent CaN5 trigonal bipyramids, edges with six CaN5 square pyramids, an edgeedge with one NbN4 tetrahedra, edges with two equivalent CaN5 trigonal bipyramids, and an edgeedge with one CaN4 trigonal pyramid. There are a spread of Ca–N bond distances ranging from 2.38–2.95 Å. In the seventh Ca2+ site, Ca2+ is bonded to four N3- atoms to form distorted CaN4 trigonal pyramids that share corners with four CaN5 square pyramids, corners with three NbN4 tetrahedra, corners with three CaN5 trigonal bipyramids, and an edgeedge with one CaN6 octahedra. There are a spread of Ca–N bond distances ranging from 2.34–2.51 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to four N3- atoms to form NbN4 tetrahedra that share corners with three equivalent CaN6 octahedra, corners with three CaN5 trigonal bipyramids, corners with two equivalent CaN4 trigonal pyramids, and edges with three CaN5 square pyramids. The corner-sharing octahedra tilt angles range from 10–15°. There are a spread of Nb–N bond distances ranging from 1.94–2.02 Å. In the second Nb5+ site, Nb5+ is bonded to four N3- atoms to form NbN4 tetrahedra that share corners with three equivalent CaN5 square pyramids, corners with six CaN5 trigonal bipyramids, a cornercorner with one CaN4 trigonal pyramid, an edgeedge with one CaN6 octahedra, and edges with two equivalent CaN5 square pyramids. There are a spread of Nb–N bond distances ranging from 1.94–2.02 Å. There are eight inequivalent N3- sites. In the first N3- site, N3- is bonded to six Ca2+ atoms to form NCa6 octahedra that share edges with eight NCa5Nb octahedra and a faceface with one NCa6 octahedra. In the second N3- site, N3- is bonded to five Ca2+ and one Nb5+ atom to form a mixture of corner and edge-sharing NCa5Nb octahedra. The corner-sharing octahedra tilt angles range from 7–56°. In the third N3- site, N3- is bonded to six Ca2+ atoms to form NCa6 octahedra that share corners with ten NCa5Nb octahedra and a faceface with one NCa6 octahedra. The corner-sharing octahedra tilt angles range from 46–56°. In the fourth N3- site, N3- is bonded in a rectangular see-saw-like geometry to three Ca2+ and one Nb5+ atom. In the fifth N3- site, N3- is bonded to five Ca2+ and one Nb5+ atom to form a mixture of corner and edge-sharing NCa5Nb octahedra. The corner-sharing octahedral tilt angles are 55°. In the sixth N3- site, N3- is bonded to five Ca2+ and one Nb5+ atom to form NCa5Nb octahedra that share corners with five NCa5Nb octahedra and edges with seven NCa6 octahedra. The corner-sharing octahedra tilt angles range from 7–50°. In the seventh N3- site, N3- is bonded in a 6-coordinate geometry to five Ca2+ and one Nb5+ atom. In the eighth N3- site, N3- is bonded in a rectangular see-saw-like geometry to three Ca2+ and one Nb5+ atom.