DOI: 10.17188/1289593
title: Materials Data on Hf2N2O by Materials Project

description: Hf2ON2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded in a 7-coordinate geometry to six N3- and one O2- atom. There are a spread of Hf–N bond distances ranging from 2.14–2.71 Å. The Hf–O bond length is 2.14 Å. In the second Hf4+ site, Hf4+ is bonded in a 7-coordinate geometry to five N3- and two O2- atoms. There are a spread of Hf–N bond distances ranging from 2.13–2.30 Å. There are one shorter (2.16 Å) and one longer (2.44 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded in a 7-coordinate geometry to five N3- and two O2- atoms. There are a spread of Hf–N bond distances ranging from 2.13–2.35 Å. There are one shorter (2.17 Å) and one longer (2.56 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded in a 7-coordinate geometry to five N3- and two O2- atoms. There are a spread of Hf–N bond distances ranging from 2.10–2.27 Å. There are one shorter (2.27 Å) and one longer (2.45 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 60–64°. There are a spread of Hf–N bond distances ranging from 2.12–2.20 Å. There are one shorter (2.14 Å) and one longer (2.15 Å) Hf–O bond lengths. In the sixth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 60–62°. There are a spread of Hf–N bond distances ranging from 2.12–2.22 Å. There are one shorter (2.12 Å) and one longer (2.17 Å) Hf–O bond lengths. In the seventh Hf4+ site, Hf4+ is bonded in a 7-coordinate geometry to four N3- and three O2- atoms. There are a spread of Hf–N bond distances ranging from 2.10–2.61 Å. There are a spread of Hf–O bond distances ranging from 2.18–2.27 Å. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 60–64°. There are a spread of Hf–N bond distances ranging from 2.14–2.18 Å. There are one shorter (2.15 Å) and one longer (2.17 Å) Hf–O bond lengths. There are eight inequivalent N3- sites. In the first N3- site, N3- is bonded to five Hf4+ atoms to form distorted NHf5 trigonal bipyramids that share corners with four equivalent NHf5 square pyramids, a cornercorner with one NHf4 tetrahedra, corners with two equivalent OHf4 tetrahedra, edges with two equivalent NHf5 square pyramids, edges with two NHf4 tetrahedra, and edges with two equivalent NHf5 trigonal bipyramids. In the second N3- site, N3- is bonded to five Hf4+ atoms to form distorted NHf5 square pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two equivalent NHf4 tetrahedra, corners with four equivalent NHf5 trigonal bipyramids, edges with two equivalent NHf5 square pyramids, edges with two NHf4 tetrahedra, and edges with two equivalent NHf5 trigonal bipyramids. In the third N3- site, N3- is bonded to five Hf4+ atoms to form distorted NHf5 trigonal bipyramids that share corners with four equivalent NHf5 square pyramids, corners with three NHf4 tetrahedra, edges with two equivalent NHf5 square pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, and edges with two equivalent NHf5 trigonal bipyramids. In the fourth N3- site, N3- is bonded to five Hf4+ atoms to form distorted NHf5 square pyramids that share corners with three NHf4 tetrahedra, corners with four equivalent NHf5 trigonal bipyramids, edges with two equivalent NHf5 square pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, and edges with two equivalent NHf5 trigonal bipyramids. In the fifth N3- site, N3- is bonded in a 5-coordinate geometry to five Hf4+ atoms. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with two equivalent NHf5 square pyramids, corners with two equivalent OHf4 tetrahedra, corners with four NHf4 tetrahedra, a cornercorner with one NHf5 trigonal bipyramid, an edgeedge with one NHf5 square pyramid, and an edgeedge with one NHf5 trigonal bipyramid. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with two equivalent NHf5 square pyramids, corners with two equivalent OHf4 tetrahedra, corners with four NHf4 tetrahedra, a cornercorner with one NHf5 trigonal bipyramid, an edgeedge with one NHf5 square pyramid, and an edgeedge with one NHf5 trigonal bipyramid. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 tetrahedra that share a cornercorner with one NHf5 square pyramid, corners with two equivalent OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with two equivalent NHf5 trigonal bipyramids, an edgeedge with one NHf5 square pyramid, and an edgeedge with one NHf5 trigonal bipyramid. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to four Hf4+ atoms. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 tetrahedra that share a cornercorner with one NHf5 square pyramid, corners with six NHf4 tetrahedra, corners with two equivalent NHf5 trigonal bipyramids, an edgeedge with one NHf5 square pyramid, and an edgeedge with one NHf5 trigonal bipyramid. In the third O2- site, O2- is bonded in a 4-coordinate geometry to four Hf4+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to four Hf4+ atoms.