Materials Data on MgTa2N3 by Materials Project

Abstract

MgTa2N3 is Caswellsilverite-like structured and crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent N3- atoms to form MgN6 octahedra that share corners with six equivalent TaN6 pentagonal pyramids, edges with three equivalent MgN6 octahedra, edges with three equivalent TaN6 octahedra, and edges with six equivalent TaN6 pentagonal pyramids. All Mg–N bond lengths are 2.16 Å. There are two inequivalent Ta+3.50+ sites. In the first Ta+3.50+ site, Ta+3.50+ is bonded to six equivalent N3- atoms to form distorted TaN6 pentagonal pyramids that share corners with two equivalent TaN6 octahedra, corners with four equivalent MgN6 octahedra, edges with two equivalent TaN6 octahedra, edges with four equivalent MgN6 octahedra, and edges with six equivalent TaN6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 2–3°. There are four shorter (2.21 Å) and two longer (2.22 Å) Ta–N bond lengths. In the second Ta+3.50+ site, Ta+3.50+ is bonded to six equivalent N3- atoms to form TaN6 octahedra that share corners with six equivalent TaN6 pentagonal pyramids, edges with six equivalent MgN6 octahedra, and edges with six equivalent TaN6 pentagonal pyramids. All Ta–N bond lengths are 2.14 Å. N3- is bonded to two equivalent Mg2+ and four Ta+3.50+ atoms to form a mixture of face, edge, and corner-sharing NMg2Ta4 octahedra. The corner-sharing octahedra tilt angles range from 0–48°.