MgTi2(NiO3)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and one O(6) atom. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted TiO5 trigonal bipyramids that share corners with three equivalent Ni(2)O6 octahedra and  an edgeedge with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-64°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(6) atom. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NiO6 octahedra that share corners with three equivalent Ti(2)O5 trigonal bipyramids and  an edgeedge with one Ti(2)O5 trigonal bipyramid. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ti(1), one Ni(1), and one Ni(2) atom to form distorted OMgTiNi2 trigonal pyramids that share corners with three equivalent O(2)MgTi2Ni tetrahedra, corners with three equivalent O(3)Ti2Ni2 tetrahedra, and edges with two equivalent O(4)MgTi2Ni2 trigonal bipyramids. In the second O site, O(2) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom to form distorted OMgTi2Ni tetrahedra that share corners with three equivalent O(3)Ti2Ni2 tetrahedra, corners with four equivalent O(4)MgTi2Ni2 trigonal bipyramids, and corners with three equivalent O(1)MgTiNi2 trigonal pyramids. In the third O site, O(3) is bonded to one Ti(1), one Ti(2), one Ni(1), and one Ni(2) atom to form distorted OTi2Ni2 tetrahedra that share corners with three equivalent O(2)MgTi2Ni tetrahedra, corners with two equivalent O(4)MgTi2Ni2 trigonal bipyramids, corners with three equivalent O(1)MgTiNi2 trigonal pyramids, and  an edgeedge with one O(4)MgTi2Ni2 trigonal bipyramid. In the fourth O site, O(4) is bonded to one Mg(1), one Ti(1), one Ti(2), one Ni(1), and one Ni(2) atom to form distorted OMgTi2Ni2 trigonal bipyramids that share corners with two equivalent O(3)Ti2Ni2 tetrahedra, corners with four equivalent O(2)MgTi2Ni tetrahedra,  an edgeedge with one O(3)Ti2Ni2 tetrahedra, and edges with two equivalent O(1)MgTiNi2 trigonal pyramids. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), one Ni(1), and one Ni(2) atom.
MgTi2(NiO3)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and one O(6) atom. The Mg(1)-O(1) bond length is 2.12 Å. The Mg(1)-O(2) bond length is 2.10 Å. The Mg(1)-O(4) bond length is 1.99 Å. The Mg(1)-O(5) bond length is 1.99 Å. The Mg(1)-O(6) bond length is 2.20 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Ti(1)-O(1) bond length is 1.86 Å. The Ti(1)-O(2) bond length is 2.04 Å. The Ti(1)-O(3) bond length is 2.07 Å. The Ti(1)-O(4) bond length is 2.19 Å. The Ti(1)-O(5) bond length is 1.95 Å. The Ti(1)-O(6) bond length is 2.39 Å. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted TiO5 trigonal bipyramids that share corners with three equivalent Ni(2)O6 octahedra and  an edgeedge with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-64°. The Ti(2)-O(2) bond length is 1.97 Å. The Ti(2)-O(3) bond length is 1.90 Å. The Ti(2)-O(4) bond length is 2.03 Å. The Ti(2)-O(5) bond length is 2.08 Å. The Ti(2)-O(6) bond length is 1.93 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(6) atom. The Ni(1)-O(1) bond length is 1.96 Å. The Ni(1)-O(3) bond length is 2.10 Å. The Ni(1)-O(4) bond length is 2.17 Å. The Ni(1)-O(6) bond length is 2.10 Å. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted NiO6 octahedra that share corners with three equivalent Ti(2)O5 trigonal bipyramids and  an edgeedge with one Ti(2)O5 trigonal bipyramid. The Ni(2)-O(1) bond length is 2.11 Å. The Ni(2)-O(2) bond length is 2.07 Å. The Ni(2)-O(3) bond length is 2.10 Å. The Ni(2)-O(4) bond length is 2.12 Å. The Ni(2)-O(5) bond length is 2.16 Å. The Ni(2)-O(6) bond length is 2.21 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ti(1), one Ni(1), and one Ni(2) atom to form distorted OMgTiNi2 trigonal pyramids that share corners with three equivalent O(2)MgTi2Ni tetrahedra, corners with three equivalent O(3)Ti2Ni2 tetrahedra, and edges with two equivalent O(4)MgTi2Ni2 trigonal bipyramids. In the second O site, O(2) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom to form distorted OMgTi2Ni tetrahedra that share corners with three equivalent O(3)Ti2Ni2 tetrahedra, corners with four equivalent O(4)MgTi2Ni2 trigonal bipyramids, and corners with three equivalent O(1)MgTiNi2 trigonal pyramids. In the third O site, O(3) is bonded to one Ti(1), one Ti(2), one Ni(1), and one Ni(2) atom to form distorted OTi2Ni2 tetrahedra that share corners with three equivalent O(2)MgTi2Ni tetrahedra, corners with two equivalent O(4)MgTi2Ni2 trigonal bipyramids, corners with three equivalent O(1)MgTiNi2 trigonal pyramids, and  an edgeedge with one O(4)MgTi2Ni2 trigonal bipyramid. In the fourth O site, O(4) is bonded to one Mg(1), one Ti(1), one Ti(2), one Ni(1), and one Ni(2) atom to form distorted OMgTi2Ni2 trigonal bipyramids that share corners with two equivalent O(3)Ti2Ni2 tetrahedra, corners with four equivalent O(2)MgTi2Ni tetrahedra,  an edgeedge with one O(3)Ti2Ni2 tetrahedra, and edges with two equivalent O(1)MgTiNi2 trigonal pyramids. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), one Ni(1), and one Ni(2) atom.