DOI: 10.17188/1758129
title: Materials Data on Nb20N17 by Materials Project

description: Nb20N17 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are eight inequivalent Nb+2.55+ sites. In the first Nb+2.55+ site, Nb+2.55+ is bonded in a square co-planar geometry to four N3- atoms. There are two shorter (2.20 Å) and two longer (2.21 Å) Nb–N bond lengths. In the second Nb+2.55+ site, Nb+2.55+ is bonded to five N3- atoms to form NbN5 square pyramids that share corners with seven NbN5 square pyramids, edges with four NbN6 octahedra, and edges with four NbN5 square pyramids. There are a spread of Nb–N bond distances ranging from 2.20–2.30 Å. In the third Nb+2.55+ site, Nb+2.55+ is bonded to five N3- atoms to form NbN5 square pyramids that share corners with eight NbN5 square pyramids, edges with three NbN6 octahedra, and edges with five NbN5 square pyramids. There are a spread of Nb–N bond distances ranging from 2.21–2.31 Å. In the fourth Nb+2.55+ site, Nb+2.55+ is bonded to five N3- atoms to form NbN5 square pyramids that share corners with five NbN6 octahedra, corners with four equivalent NbN5 square pyramids, an edgeedge with one NbN6 octahedra, and edges with five NbN5 square pyramids. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Nb–N bond distances ranging from 2.21–2.28 Å. In the fifth Nb+2.55+ site, Nb+2.55+ is bonded to six N3- atoms to form NbN6 octahedra that share a cornercorner with one NbN6 octahedra, corners with five NbN5 square pyramids, an edgeedge with one NbN6 octahedra, and edges with nine NbN5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are five shorter (2.22 Å) and one longer (2.27 Å) Nb–N bond lengths. In the sixth Nb+2.55+ site, Nb+2.55+ is bonded to five N3- atoms to form NbN5 square pyramids that share corners with three NbN6 octahedra, corners with four NbN5 square pyramids, edges with two equivalent NbN6 octahedra, and edges with six NbN5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. There are four shorter (2.22 Å) and one longer (2.24 Å) Nb–N bond lengths. In the seventh Nb+2.55+ site, Nb+2.55+ is bonded to five N3- atoms to form NbN5 square pyramids that share corners with two equivalent NbN6 octahedra, corners with five NbN5 square pyramids, edges with two NbN6 octahedra, and edges with six NbN5 square pyramids. The corner-sharing octahedral tilt angles are 2°. There are a spread of Nb–N bond distances ranging from 2.20–2.30 Å. In the eighth Nb+2.55+ site, Nb+2.55+ is bonded to six N3- atoms to form NbN6 octahedra that share a cornercorner with one NbN6 octahedra, corners with five NbN5 square pyramids, edges with two equivalent NbN6 octahedra, and edges with ten NbN5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are a spread of Nb–N bond distances ranging from 2.21–2.26 Å. There are seven inequivalent N3- sites. In the first N3- site, N3- is bonded to six Nb+2.55+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second N3- site, N3- is bonded to six Nb+2.55+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedral tilt angles are 5°. In the third N3- site, N3- is bonded to six Nb+2.55+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the fourth N3- site, N3- is bonded to six Nb+2.55+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the fifth N3- site, N3- is bonded to six Nb+2.55+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the sixth N3- site, N3- is bonded to six Nb+2.55+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the seventh N3- site, N3- is bonded to six Nb+2.55+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedra tilt angles range from 1–8°.