DOI: 10.17188/1306878
title: Materials Data on Hf2N2O by Materials Project

description: Hf2ON2 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are twelve inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded in a 7-coordinate geometry to three N3- and four O2- atoms. There are a spread of Hf–N bond distances ranging from 2.06–2.49 Å. There are two shorter (2.16 Å) and two longer (2.28 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded in a 7-coordinate geometry to three N3- and four O2- atoms. There are two shorter (2.14 Å) and one longer (2.30 Å) Hf–N bond lengths. There are two shorter (2.14 Å) and two longer (2.33 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with two equivalent HfN4O2 octahedra, a cornercorner with one HfN5O2 pentagonal bipyramid, edges with three HfN5O octahedra, and edges with two equivalent HfN4O3 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 10°. There are a spread of Hf–N bond distances ranging from 2.10–2.31 Å. The Hf–O bond length is 2.15 Å. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with two equivalent HfN5O octahedra, a cornercorner with one HfN5O2 pentagonal bipyramid, edges with three HfN5O octahedra, and edges with two equivalent HfN4O3 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 10°. There are two shorter (2.13 Å) and two longer (2.27 Å) Hf–N bond lengths. There are one shorter (2.08 Å) and one longer (2.14 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded in a 6-coordinate geometry to three N3- and three O2- atoms. There are one shorter (2.08 Å) and two longer (2.29 Å) Hf–N bond lengths. There are two shorter (2.11 Å) and one longer (2.29 Å) Hf–O bond lengths. In the sixth Hf4+ site, Hf4+ is bonded to four N3- and three O2- atoms to form distorted HfN4O3 pentagonal bipyramids that share a cornercorner with one HfN6 octahedra, edges with four HfN5O octahedra, and edges with two equivalent HfN4O3 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of Hf–N bond distances ranging from 2.10–2.37 Å. There are two shorter (2.16 Å) and one longer (2.24 Å) Hf–O bond lengths. In the seventh 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 2.09–2.41 Å. There are one shorter (2.24 Å) and one longer (2.46 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded in a 6-coordinate geometry to three N3- and three O2- atoms. There are one shorter (2.05 Å) and two longer (2.19 Å) Hf–N bond lengths. There are two shorter (2.21 Å) and one longer (2.43 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to six N3- atoms to form HfN6 octahedra that share corners with two equivalent HfN6 octahedra, a cornercorner with one HfN4O3 pentagonal bipyramid, and edges with three HfN6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are a spread of Hf–N bond distances ranging from 2.13–2.29 Å. In the tenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form HfN6 octahedra that share corners with two equivalent HfN6 octahedra, edges with three HfN6 octahedra, and edges with two equivalent HfN5O2 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 15°. There are a spread of Hf–N bond distances ranging from 2.10–2.31 Å. In the eleventh 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 2.15–2.37 Å. The Hf–O bond length is 2.28 Å. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and two O2- atoms to form distorted HfN5O2 pentagonal bipyramids that share corners with two HfN4O2 octahedra, edges with two equivalent HfN6 octahedra, and edges with two equivalent HfN5O2 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 38–42°. There are a spread of Hf–N bond distances ranging from 2.14–2.34 Å. There are one shorter (2.21 Å) and one longer (2.29 Å) Hf–O bond lengths. There are twelve 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 NHf4 tetrahedra that share corners with two equivalent NHf5 square pyramids, corners with two equivalent OHf5 square pyramids, corners with two equivalent NHf4 tetrahedra, corners with two equivalent OHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, an edgeedge with one NHf5 square pyramid, and edges with two equivalent OHf4 tetrahedra. In the third N3- site, N3- is bonded to five Hf4+ atoms to form NHf5 square pyramids that share corners with three NHf4 tetrahedra, corners with four OHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, edges with two equivalent NHf5 square pyramids, an edgeedge with one NHf4 tetrahedra, and edges with two equivalent OHf4 tetrahedra. In the fourth N3- site, N3- is bonded in a 5-coordinate geometry to five Hf4+ atoms. In the fifth N3- site, N3- is bonded to five Hf4+ atoms to form distorted NHf5 square pyramids that share corners with two equivalent OHf4 tetrahedra, corners with three NHf4 tetrahedra, corners with two equivalent OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, edges with four NHf5 square pyramids, an edgeedge with one NHf4 tetrahedra, and an edgeedge with one OHf4 trigonal pyramid. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf5 square pyramids, corners with three NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with two equivalent NHf4 trigonal pyramids, edges with three NHf5 square pyramids, and edges with two equivalent OHf4 tetrahedra. In the seventh N3- site, N3- is bonded to five Hf4+ atoms to form NHf5 square pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, edges with four NHf5 square pyramids, edges with two equivalent NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf5 square pyramid, corners with four NHf5 square pyramids, corners with two equivalent NHf4 tetrahedra, corners with two equivalent OHf4 trigonal pyramids, corners with three NHf4 trigonal pyramids, an edgeedge with one NHf5 square pyramid, and edges with two equivalent NHf4 tetrahedra. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf5 square pyramid, corners with four NHf5 square pyramids, corners with two equivalent NHf4 tetrahedra, corners with two OHf4 tetrahedra, corners with three NHf4 trigonal pyramids, an edgeedge with one NHf5 square pyramid, and edges with two equivalent NHf4 tetrahedra. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with two equivalent OHf5 square pyramids, corners with three NHf5 square pyramids, corners with two equivalent OHf4 tetrahedra, corners with three NHf4 tetrahedra, edges with two equivalent OHf4 tetrahedra, and edges with two equivalent NHf4 trigonal pyramids. In the eleventh 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, corners with two equivalent NHf4 trigonal pyramids, edges with two equivalent OHf5 square pyramids, and edges with two equivalent NHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded in a 5-coordinate geometry to five Hf4+ atoms. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to five Hf4+ atoms to form distorted OHf5 square pyramids that share corners with four NHf4 tetrahedra, corners with four OHf4 tetrahedra, corners with two NHf4 trigonal pyramids, edges with two equivalent OHf5 square pyramids, edges with two equivalent NHf4 tetrahedra, and edges with two OHf4 tetrahedra. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 tetrahedra that share corners with two equivalent NHf5 square pyramids, corners with two equivalent OHf5 square pyramids, corners with two equivalent NHf4 tetrahedra, corners with four OHf4 tetrahedra, a cornercorner with one NHf4 trigonal pyramid, an edgeedge with one OHf5 square pyramid, and edges with two equivalent NHf4 tetrahedra. In the third O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 tetrahedra that share corners with two equivalent NHf5 square pyramids, corners with two equivalent OHf5 square pyramids, corners with two equivalent NHf4 tetrahedra, corners with three OHf4 tetrahedra, a cornercorner with one NHf4 trigonal pyramid, an edgeedge with one OHf5 square pyramid, and edges with two equivalent NHf4 tetrahedra. In the fourth O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 tetrahedra that share corners with three NHf5 square pyramids, corners with two equivalent NHf4 tetrahedra, corners with three OHf4 tetrahedra, corners with two equivalent OHf4 trigonal pyramids, edges with two equivalent NHf5 square pyramids, and edges with two equivalent NHf4 tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to four Hf4+ atoms. In the sixth O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with three NHf5 square pyramids, corners with two NHf4 tetrahedra, corners with two equivalent OHf4 tetrahedra, corners with two equivalent NHf4 trigonal pyramids, corners with two equivalent OHf4 trigonal pyramids, and an edgeedge with one NHf5 square pyramid.