MgTi2(NiO3)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 6-coordinate geometry to one Ni(1), 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 to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted TiO6 octahedra that share corners with five equivalent Ti(2)O5 trigonal bipyramids and edges with three equivalent Ni(2)O6 octahedra. 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, corners with five equivalent Ti(1)O6 octahedra, and  an edgeedge with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-62°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one O(1), one O(3), 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, edges with three equivalent Ti(1)O6 octahedra, 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 corner-sharing OMgTiNi2 trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom. 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 corner-sharing OTi2Ni2 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like 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 6-coordinate geometry to one Ni(1), one O(1), one O(2), one O(4), one O(5), and one O(6) atom. The Mg(1)-Ni(1) bond length is 2.57 Å. The Mg(1)-O(1) bond length is 2.16 Å. The Mg(1)-O(2) bond length is 2.11 Å. The Mg(1)-O(4) bond length is 1.98 Å. The Mg(1)-O(5) bond length is 1.97 Å. The Mg(1)-O(6) bond length is 2.51 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) 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 TiO6 octahedra that share corners with five equivalent Ti(2)O5 trigonal bipyramids and edges with three equivalent Ni(2)O6 octahedra. The Ti(1)-O(1) bond length is 1.91 Å. The Ti(1)-O(2) bond length is 1.95 Å. The Ti(1)-O(3) bond length is 2.12 Å. The Ti(1)-O(4) bond length is 2.17 Å. The Ti(1)-O(5) bond length is 1.96 Å. The Ti(1)-O(6) bond length is 2.11 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, corners with five equivalent Ti(1)O6 octahedra, and  an edgeedge with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 24-62°. The Ti(2)-O(2) bond length is 2.06 Å. The Ti(2)-O(3) bond length is 1.86 Å. The Ti(2)-O(4) bond length is 1.94 Å. The Ti(2)-O(5) bond length is 2.10 Å. The Ti(2)-O(6) bond length is 1.94 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one O(1), one O(3), and one O(6) atom. The Ni(1)-O(1) bond length is 1.88 Å. The Ni(1)-O(3) bond length is 1.90 Å. The Ni(1)-O(6) bond length is 1.99 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, edges with three equivalent Ti(1)O6 octahedra, and  an edgeedge with one Ti(2)O5 trigonal bipyramid. The Ni(2)-O(1) bond length is 2.06 Å. The Ni(2)-O(2) bond length is 2.34 Å. The Ni(2)-O(3) bond length is 2.10 Å. The Ni(2)-O(4) bond length is 2.09 Å. The Ni(2)-O(5) bond length is 2.06 Å. The Ni(2)-O(6) bond length is 2.28 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 corner-sharing OMgTiNi2 trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom. 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 corner-sharing OTi2Ni2 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ti(1), one Ti(2), and one Ni(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like 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.