MgHo4Ti2O10 is Aluminum carbonitride-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with four equivalent Ti(1)O5 trigonal bipyramids and edges with two equivalent Mg(1)O6 octahedra. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 5-coordinate geometry to one O(2), one O(5), and three equivalent O(3) atoms. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to one O(5), two equivalent O(1), and three equivalent O(4) atoms. Ti(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(5) atoms to form TiO5 trigonal bipyramids that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 59°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Ho(2) and one Ti(1) atom. In the second O site, O(2) is bonded to two equivalent Mg(1), one Ho(1), and one Ti(1) atom to form distorted OHoMg2Ti trigonal pyramids that share  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with three equivalent O(5)Ho2Ti2 tetrahedra, corners with three equivalent O(3)Ho3Mg tetrahedra, corners with four equivalent O(2)HoMg2Ti trigonal pyramids, edges with two equivalent O(3)Ho3Mg tetrahedra, and  an edgeedge with one O(2)HoMg2Ti trigonal pyramid. In the third O site, O(3) is bonded to one Mg(1) and three equivalent Ho(1) atoms to form OHo3Mg tetrahedra that share corners with three equivalent O(5)Ho2Ti2 tetrahedra, corners with three equivalent O(3)Ho3Mg tetrahedra, corners with three equivalent O(2)HoMg2Ti trigonal pyramids, edges with two equivalent O(3)Ho3Mg tetrahedra, and edges with two equivalent O(2)HoMg2Ti trigonal pyramids. In the fourth O site, O(4) is bonded to three equivalent Ho(2) and one Ti(1) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(5)Ho2Ti2 tetrahedra, corners with two equivalent O(4)Ho3Ti tetrahedra,  a cornercorner with one O(2)HoMg2Ti trigonal pyramid, edges with two equivalent O(5)Ho2Ti2 tetrahedra, and edges with two equivalent O(4)Ho3Ti tetrahedra. In the fifth O site, O(5) is bonded to one Ho(1), one Ho(2), and two equivalent Ti(1) atoms to form OHo2Ti2 tetrahedra that share  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with two equivalent O(5)Ho2Ti2 tetrahedra, corners with three equivalent O(3)Ho3Mg tetrahedra, corners with three equivalent O(2)HoMg2Ti trigonal pyramids, and edges with two equivalent O(4)Ho3Ti tetrahedra.
MgHo4Ti2O10 is Aluminum carbonitride-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with four equivalent Ti(1)O5 trigonal bipyramids and edges with two equivalent Mg(1)O6 octahedra. Both Mg(1)-O(3) bond lengths are 1.97 Å. All Mg(1)-O(2) bond lengths are 2.39 Å. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 5-coordinate geometry to one O(2), one O(5), and three equivalent O(3) atoms. The Ho(1)-O(2) bond length is 2.29 Å. The Ho(1)-O(5) bond length is 2.26 Å. There are two shorter (2.20 Å) and one longer (2.23 Å) Ho(1)-O(3) bond length. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to one O(5), two equivalent O(1), and three equivalent O(4) atoms. The Ho(2)-O(5) bond length is 2.45 Å. There is one shorter (2.22 Å) and one longer (2.30 Å) Ho(2)-O(1) bond length. There are two shorter (2.14 Å) and one longer (2.30 Å) Ho(2)-O(4) bond length. Ti(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(5) atoms to form TiO5 trigonal bipyramids that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 59°. The Ti(1)-O(1) bond length is 1.95 Å. The Ti(1)-O(2) bond length is 1.86 Å. The Ti(1)-O(4) bond length is 2.10 Å. Both Ti(1)-O(5) bond lengths are 2.12 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Ho(2) and one Ti(1) atom. In the second O site, O(2) is bonded to two equivalent Mg(1), one Ho(1), and one Ti(1) atom to form distorted OHoMg2Ti trigonal pyramids that share  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with three equivalent O(5)Ho2Ti2 tetrahedra, corners with three equivalent O(3)Ho3Mg tetrahedra, corners with four equivalent O(2)HoMg2Ti trigonal pyramids, edges with two equivalent O(3)Ho3Mg tetrahedra, and  an edgeedge with one O(2)HoMg2Ti trigonal pyramid. In the third O site, O(3) is bonded to one Mg(1) and three equivalent Ho(1) atoms to form OHo3Mg tetrahedra that share corners with three equivalent O(5)Ho2Ti2 tetrahedra, corners with three equivalent O(3)Ho3Mg tetrahedra, corners with three equivalent O(2)HoMg2Ti trigonal pyramids, edges with two equivalent O(3)Ho3Mg tetrahedra, and edges with two equivalent O(2)HoMg2Ti trigonal pyramids. In the fourth O site, O(4) is bonded to three equivalent Ho(2) and one Ti(1) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(5)Ho2Ti2 tetrahedra, corners with two equivalent O(4)Ho3Ti tetrahedra,  a cornercorner with one O(2)HoMg2Ti trigonal pyramid, edges with two equivalent O(5)Ho2Ti2 tetrahedra, and edges with two equivalent O(4)Ho3Ti tetrahedra. In the fifth O site, O(5) is bonded to one Ho(1), one Ho(2), and two equivalent Ti(1) atoms to form OHo2Ti2 tetrahedra that share  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with two equivalent O(5)Ho2Ti2 tetrahedra, corners with three equivalent O(3)Ho3Mg tetrahedra, corners with three equivalent O(2)HoMg2Ti trigonal pyramids, and edges with two equivalent O(4)Ho3Ti tetrahedra.