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Cr3N4 crystallizes in the cubic I-43d space group. The structure is three-dimensional. Cr4+ is bonded to four equivalent N3- atoms to form corner-sharing CrN4 tetrahedra. All Cr–N bond lengths are 1.84 Å. N3- is bonded in a trigonal planar geometry to three equivalent Cr4+ atoms.
Cr3N4 is Corundum-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to six N3- atoms to form CrN6 octahedra that share corners with four equivalent CrN6 octahedra, corners with two equivalent CrN4 tetrahedra, edges with four CrN6 octahedra, and edges with two equivalent CrN4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Cr–N bond distances ranging from 2.00–2.06 Å. In the second Cr4+ site, Cr4+ is bonded to six N3- atoms to form CrN6 octahedra that share corners with eight CrN6 octahedra, corners with four equivalent CrN4 tetrahedra, edges with two equivalent CrN6 octahedra, and an edgeedge with one CrN4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–55°. There are a spread of Cr–N bond distances ranging from 2.03–2.10 Å. In the third Cr4+ site, Cr4+ is bonded to four N3- atoms to form a mixture of edge and corner-sharing CrN4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–62°. There are a spread of Cr–N bond distances ranging from 1.76–1.78 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded to four Cr4+ atoms to form distorted corner-sharing NCr4 trigonal pyramids. In the second N3- site, N3- is bonded in a rectangular see-saw-like geometry to four Cr4+ atoms. In the third N3- site, N3- is bonded in a rectangular see-saw-like geometry to four Cr4+ atoms.
Cr3N4 is Corundum-like structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to six N3- atoms to form a mixture of corner, edge, and face-sharing CrN6 octahedra. The corner-sharing octahedra tilt angles range from 43–49°. There are a spread of Cr–N bond distances ranging from 1.90–2.04 Å. In the second Cr4+ site, Cr4+ is bonded to six N3- atoms to form a mixture of corner, edge, and face-sharing CrN6 octahedra. The corner-sharing octahedra tilt angles range from 43–49°. There are a spread of Cr–N bond distances ranging from 1.91–2.04 Å. In the third Cr4+ site, Cr4+ is bonded to six N3- atoms to form a mixture of corner, edge, and face-sharing CrN6 octahedra. The corner-sharing octahedra tilt angles range from 43–49°. There are a spread of Cr–N bond distances ranging from 1.90–2.04 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded to four Cr4+ atoms to form NCr4 trigonal pyramids that share corners with two equivalent NCr6 pentagonal pyramids, corners with eight NCr4 trigonal pyramids, edges with three equivalent NCr6 pentagonal pyramids, and edges with two equivalent NCr4 trigonal pyramids. In the second N3- site, N3- is bonded to four Cr4+ atoms to form NCr4 trigonal pyramids that share corners with two equivalent NCr6 pentagonal pyramids, corners with eight NCr4 trigonal pyramids, edges with three equivalent NCr6 pentagonal pyramids, and edges with two equivalent NCr4 trigonal pyramids. In the third N3- site, N3- is bonded to four Cr4+ atoms to form NCr4 trigonal pyramids that share corners with two equivalent NCr6 pentagonal pyramids, corners with eight NCr4 trigonal pyramids, edges with three equivalent NCr6 pentagonal pyramids, and edges with two equivalent NCr4 trigonal pyramids. In the fourth N3- site, N3- is bonded to six Cr4+ atoms to form distorted NCr6 pentagonal pyramids that share corners with six NCr4 trigonal pyramids, edges with nine NCr4 trigonal pyramids, and faces with two equivalent NCr6 pentagonal pyramids.
Cr3N4 crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cr4+ is bonded to six N3- atoms to form a mixture of edge and corner-sharing CrN6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Cr–N bond lengths are 1.98 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a square co-planar geometry to four equivalent Cr4+ atoms. In the second N3- site, N3- is bonded to six equivalent Cr4+ atoms to form corner-sharing NCr6 octahedra. The corner-sharing octahedral tilt angles are 0°.
Cr3N4 is Hausmannite structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are two inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to four equivalent N3- atoms to form corner-sharing CrN4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. All Cr–N bond lengths are 1.82 Å. In the second Cr4+ site, Cr4+ is bonded to six equivalent N3- atoms to form CrN6 octahedra that share corners with six equivalent CrN4 tetrahedra and edges with six equivalent CrN6 octahedra. All Cr–N bond lengths are 2.02 Å. N3- is bonded in a distorted rectangular see-saw-like geometry to four Cr4+ atoms.
Cr3N4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are six inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.84–1.86 Å. In the second Cr4+ site, Cr4+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.84–1.86 Å. In the third Cr4+ site, Cr4+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.84–1.86 Å. In the fourth Cr4+ site, Cr4+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There is two shorter (1.83 Å) and two longer (1.84 Å) Cr–N bond length. In the fifth Cr4+ site, Cr4+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There is two shorter (1.83 Å) and two longer (1.84 Å) Cr–N bond length. In the sixth Cr4+ site, Cr4+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There is two shorter (1.83 Å) and two longer (1.84 Å) Cr–N bond length. There are eight inequivalent N3- sites. In the first N3- site, N3- is bonded in a trigonal planar geometry to three Cr4+ atoms. In the second N3- site, N3- is bonded in a trigonal planar geometry to three Cr4+ atoms. In the third N3- site, N3- is bonded in a trigonal non-coplanar geometry to three Cr4+ atoms. In the fourth N3- site, N3- is bonded in a trigonal planar geometry to three Cr4+ atoms. In the fifth N3- site, N3- is bonded in a trigonal planar geometry to three Cr4+ atoms. In the sixth N3- site, N3- is bonded in a trigonal planar geometry to three Cr4+ atoms. In the seventh N3- site, N3- is bonded in a trigonal planar geometry to three Cr4+ atoms. In the eighth N3- site, N3- is bonded in a trigonal planar geometry to three Cr4+ atoms.