Materials Data on Hf2N2O by Materials Project

Abstract

Hf2ON2 is beta indium sulfide-derived structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are three inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four equivalent N3- and two equivalent O2- atoms to form HfN4O2 octahedra that share corners with four equivalent HfN4 tetrahedra and edges with six HfN4O2 octahedra. All Hf–N bond lengths are 2.21 Å. Both Hf–O bond lengths are 2.08 Å. In the second Hf4+ site, Hf4+ is bonded to four N3- and two equivalent O2- atoms to form HfN4O2 octahedra that share corners with four equivalent HfN4 tetrahedra and edges with six HfN4O2 octahedra. There are a spread of Hf–N bond distances ranging from 2.19–2.23 Å. Both Hf–O bond lengths are 2.10 Å. In the third Hf4+ site, Hf4+ is bonded to four N3- atoms to form corner-sharing HfN4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–58°. There are two shorter (2.08 Å) and two longer (2.09 Å) Hf–N bond lengths. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form a mixture of distorted corner and edge-sharing NHf4 trigonal pyramids. In the second N3- site, N3- is bonded in a distorted rectangular see-saw-like geometry to four Hf4+ atoms. O2- is bonded in a distorted trigonal non-coplanar geometry to three Hf4+ atoms.