NiAl2O4 is Spinel structured and crystallizes in the tetragonal I4_1md space group. Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NiO4 tetrahedra that share corners with twelve equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 58-63°. Al(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form AlO6 octahedra that share corners with six equivalent Ni(1)O4 tetrahedra and edges with six equivalent Al(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ni(1) and three equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl3Ni trigonal pyramids. In the second O site, O(2) is bonded to one Ni(1) and three equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl3Ni trigonal pyramids.
NiAl2O4 is Spinel structured and crystallizes in the tetragonal I4_1md space group. Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NiO4 tetrahedra that share corners with twelve equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 58-63°. Both Ni(1)-O(1) bond lengths are 1.96 Å. Both Ni(1)-O(2) bond lengths are 1.98 Å. Al(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form AlO6 octahedra that share corners with six equivalent Ni(1)O4 tetrahedra and edges with six equivalent Al(1)O6 octahedra. There are two shorter (1.93 Å) and one longer (1.94 Å) Al(1)-O(1) bond length. There is one shorter (1.92 Å) and two longer (1.94 Å) Al(1)-O(2) bond lengths. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ni(1) and three equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl3Ni trigonal pyramids. In the second O site, O(2) is bonded to one Ni(1) and three equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl3Ni trigonal pyramids.