Materials Data on Nb3AlN4 by Materials Project

Abstract

Nb3AlN4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Nb3+ sites. In the first Nb3+ site, Nb3+ is bonded to six N3- atoms to form NbN6 octahedra that share corners with three equivalent NbN6 octahedra, corners with three equivalent AlN6 octahedra, edges with three equivalent AlN6 octahedra, and edges with nine NbN6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are three shorter (2.20 Å) and three longer (2.29 Å) Nb–N bond lengths. In the second Nb3+ site, Nb3+ is bonded to six equivalent N3- atoms to form a mixture of edge and corner-sharing NbN6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Nb–N bond lengths are 2.20 Å. Al3+ is bonded to six equivalent N3- atoms to form AlN6 octahedra that share corners with six equivalent NbN6 octahedra, edges with six equivalent NbN6 octahedra, and edges with six equivalent AlN6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Al–N bond lengths are 2.07 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded to six Nb3+ atoms to form a mixture of edge and corner-sharing NNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the second N3- site, N3- is bonded to three equivalent Nb3+ and three equivalent Al3+ atoms to form a mixture of edge and corner-sharing NNb3Al3 octahedra. The corner-sharing octahedra tilt angles range from 0–3°.