NiGa2O4 is Spinel structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(5), and two equivalent O(4) atoms to form NiO4 tetrahedra that share  a cornercorner with one Ga(1)O6 octahedra, corners with two equivalent Ga(2)O6 octahedra, corners with two equivalent Ga(4)O6 octahedra, corners with three equivalent Ga(5)O6 octahedra, and corners with four equivalent Ga(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. In the second Ni site, Ni(2) is bonded to one O(2), one O(6), and two equivalent O(3) atoms to form NiO4 tetrahedra that share  a cornercorner with one Ga(2)O6 octahedra, corners with two equivalent Ga(1)O6 octahedra, corners with two equivalent Ga(3)O6 octahedra, corners with three equivalent Ga(5)O6 octahedra, and corners with four equivalent Ga(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-61°. There are five inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form GaO6 octahedra that share corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Ni(2)O4 tetrahedra, edges with two equivalent Ga(5)O6 octahedra, and edges with four equivalent Ga(4)O6 octahedra. In the second Ga site, Ga(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form GaO6 octahedra that share corners with two equivalent Ni(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ga(5)O6 octahedra, and edges with four equivalent Ga(3)O6 octahedra. In the third Ga site, Ga(3) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form GaO6 octahedra that share corners with two equivalent Ni(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ga(2)O6 octahedra, edges with two equivalent Ga(3)O6 octahedra, and edges with two equivalent Ga(5)O6 octahedra. In the fourth Ga site, Ga(4) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form GaO6 octahedra that share corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Ni(2)O4 tetrahedra, edges with two equivalent Ga(1)O6 octahedra, edges with two equivalent Ga(4)O6 octahedra, and edges with two equivalent Ga(5)O6 octahedra. In the fifth Ga site, Ga(5) is bonded to one O(5), one O(6), two equivalent O(3), and two equivalent O(4) atoms to form GaO6 octahedra that share corners with three equivalent Ni(1)O4 tetrahedra, corners with three equivalent Ni(2)O4 tetrahedra,  an edgeedge with one Ga(1)O6 octahedra,  an edgeedge with one Ga(2)O6 octahedra, edges with two equivalent Ga(3)O6 octahedra, and edges with two equivalent Ga(4)O6 octahedra. There are six inequivalent O sites. In the first O site, O(5) is bonded to one Ni(1), one Ga(5), and two equivalent Ga(3) atoms to form distorted corner-sharing OGa3Ni trigonal pyramids. In the second O site, O(6) is bonded in a rectangular see-saw-like geometry to one Ni(2), one Ga(5), and two equivalent Ga(4) atoms. In the third O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ni(1), one Ga(1), and two equivalent Ga(4) atoms. In the fourth O site, O(2) is bonded in a rectangular see-saw-like geometry to one Ni(2), one Ga(2), and two equivalent Ga(3) atoms. In the fifth O site, O(3) is bonded in a rectangular see-saw-like geometry to one Ni(2), one Ga(1), one Ga(4), and one Ga(5) atom. In the sixth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Ni(1), one Ga(2), one Ga(3), and one Ga(5) atom.
NiGa2O4 is Spinel structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(5), and two equivalent O(4) atoms to form NiO4 tetrahedra that share  a cornercorner with one Ga(1)O6 octahedra, corners with two equivalent Ga(2)O6 octahedra, corners with two equivalent Ga(4)O6 octahedra, corners with three equivalent Ga(5)O6 octahedra, and corners with four equivalent Ga(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. The Ni(1)-O(1) bond length is 2.02 Å. The Ni(1)-O(5) bond length is 2.00 Å. Both Ni(1)-O(4) bond lengths are 1.99 Å. In the second Ni site, Ni(2) is bonded to one O(2), one O(6), and two equivalent O(3) atoms to form NiO4 tetrahedra that share  a cornercorner with one Ga(2)O6 octahedra, corners with two equivalent Ga(1)O6 octahedra, corners with two equivalent Ga(3)O6 octahedra, corners with three equivalent Ga(5)O6 octahedra, and corners with four equivalent Ga(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-61°. The Ni(2)-O(2) bond length is 1.99 Å. The Ni(2)-O(6) bond length is 1.99 Å. Both Ni(2)-O(3) bond lengths are 1.99 Å. There are five inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form GaO6 octahedra that share corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Ni(2)O4 tetrahedra, edges with two equivalent Ga(5)O6 octahedra, and edges with four equivalent Ga(4)O6 octahedra. Both Ga(1)-O(1) bond lengths are 2.00 Å. All Ga(1)-O(3) bond lengths are 2.03 Å. In the second Ga site, Ga(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form GaO6 octahedra that share corners with two equivalent Ni(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ga(5)O6 octahedra, and edges with four equivalent Ga(3)O6 octahedra. Both Ga(2)-O(2) bond lengths are 2.02 Å. All Ga(2)-O(4) bond lengths are 2.01 Å. In the third Ga site, Ga(3) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form GaO6 octahedra that share corners with two equivalent Ni(2)O4 tetrahedra, corners with four equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ga(2)O6 octahedra, edges with two equivalent Ga(3)O6 octahedra, and edges with two equivalent Ga(5)O6 octahedra. Both Ga(3)-O(2) bond lengths are 2.02 Å. Both Ga(3)-O(4) bond lengths are 2.02 Å. Both Ga(3)-O(5) bond lengths are 2.01 Å. In the fourth Ga site, Ga(4) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form GaO6 octahedra that share corners with two equivalent Ni(1)O4 tetrahedra, corners with four equivalent Ni(2)O4 tetrahedra, edges with two equivalent Ga(1)O6 octahedra, edges with two equivalent Ga(4)O6 octahedra, and edges with two equivalent Ga(5)O6 octahedra. Both Ga(4)-O(1) bond lengths are 2.01 Å. Both Ga(4)-O(3) bond lengths are 2.02 Å. Both Ga(4)-O(6) bond lengths are 2.03 Å. In the fifth Ga site, Ga(5) is bonded to one O(5), one O(6), two equivalent O(3), and two equivalent O(4) atoms to form GaO6 octahedra that share corners with three equivalent Ni(1)O4 tetrahedra, corners with three equivalent Ni(2)O4 tetrahedra,  an edgeedge with one Ga(1)O6 octahedra,  an edgeedge with one Ga(2)O6 octahedra, edges with two equivalent Ga(3)O6 octahedra, and edges with two equivalent Ga(4)O6 octahedra. The Ga(5)-O(5) bond length is 2.04 Å. The Ga(5)-O(6) bond length is 2.01 Å. Both Ga(5)-O(3) bond lengths are 2.03 Å. Both Ga(5)-O(4) bond lengths are 2.02 Å. There are six inequivalent O sites. In the first O site, O(5) is bonded to one Ni(1), one Ga(5), and two equivalent Ga(3) atoms to form distorted corner-sharing OGa3Ni trigonal pyramids. In the second O site, O(6) is bonded in a rectangular see-saw-like geometry to one Ni(2), one Ga(5), and two equivalent Ga(4) atoms. In the third O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ni(1), one Ga(1), and two equivalent Ga(4) atoms. In the fourth O site, O(2) is bonded in a rectangular see-saw-like geometry to one Ni(2), one Ga(2), and two equivalent Ga(3) atoms. In the fifth O site, O(3) is bonded in a rectangular see-saw-like geometry to one Ni(2), one Ga(1), one Ga(4), and one Ga(5) atom. In the sixth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Ni(1), one Ga(2), one Ga(3), and one Ga(5) atom.