Materials Data on Hf2N2O by Materials Project

Abstract

Hf2ON2 is Ilmenite-like structured and crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are two inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four N3- and two equivalent O2- atoms to form a mixture of distorted corner, edge, and face-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 43–69°. There are a spread of Hf–N bond distances ranging from 2.03–2.22 Å. There are one shorter (2.17 Å) and one longer (2.49 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to four N3- and two equivalent O2- atoms to form a mixture of distorted corner, edge, and face-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 46–69°. There are a spread of Hf–N bond distances ranging from 2.09–2.36 Å. There are one shorter (2.07 Å) and one longer (2.26 Å) Hf–O bond lengths. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a 4-coordinate geometry to four Hf4+ atoms. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted corner-sharing NHf4 trigonal pyramids. O2- is bonded in a 4-coordinate geometry to four Hf4+ atoms.