Materials Data on Hf2N2O by Materials Project

Abstract

Hf2ON2 is Ilmenite-like structured and crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. there are two inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to three N3- and three equivalent O2- atoms to form a mixture of distorted face, edge, and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 47–63°. There are a spread of Hf–N bond distances ranging from 2.06–2.23 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.31 Å. In the second Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with nine HfN3O3 octahedra, edges with three HfN3O3 octahedra, and a faceface with one HfN5O octahedra. The corner-sharing octahedra tilt angles range from 47–63°. There are a spread of Hf–N bond distances ranging from 2.10–2.29 Å. The Hf–O bond length is 2.17 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four equivalent OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four equivalent OHf4 trigonal pyramids, corners with eight equivalent NHf4 trigonal pyramids, edges with two equivalent NHf4 trigonal pyramids, and edges with two equivalent OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four equivalent NHf4 trigonal pyramids, corners with eight equivalent OHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two equivalent OHf4 trigonal pyramids, corners with ten NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two equivalent OHf4 trigonal pyramids.