Ho10Ti6O27 crystallizes in the monoclinic Cm space group. There are seven inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to one O(11), one O(13), one O(15), one O(17), one O(2), one O(7), and one O(9) atom to form distorted HoO7 pentagonal bipyramids that share  a cornercorner with one Ho(3)O6 octahedra,  a cornercorner with one Ho(1)O7 pentagonal bipyramid, and  an edgeedge with one Ho(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 71°. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), and one O(7) atom. In the third Ho site, Ho(3) is bonded to one O(19), one O(6), two equivalent O(11), and two equivalent O(12) atoms to form distorted corner-sharing HoO6 octahedra. In the fourth Ho site, Ho(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(16), one O(17), one O(19), one O(5), and one O(6) atom. In the fifth Ho site, Ho(5) is bonded in a 7-coordinate geometry to one O(4), one O(8), one O(9), two equivalent O(3), and two equivalent O(7) atoms. In the sixth Ho site, Ho(6) is bonded in a 3-coordinate geometry to one O(14), two equivalent O(10), and two equivalent O(5) atoms. In the seventh Ho site, Ho(7) is bonded in a 7-coordinate geometry to one O(13), one O(14), one O(16), two equivalent O(11), and two equivalent O(12) atoms. There are five inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(15), one O(6), two equivalent O(17), and two equivalent O(2) atoms. In the second Ti site, Ti(2) is bonded in a 5-coordinate geometry to one O(1), one O(18), one O(19), and two equivalent O(10) atoms. In the third Ti site, Ti(3) is bonded in a 7-coordinate geometry to one O(10), one O(12), one O(14), one O(18), one O(3), one O(5), and one O(8) atom. In the fourth Ti site, Ti(4) is bonded in a 6-coordinate geometry to one O(13), one O(16), one O(4), one O(9), and two equivalent O(17) atoms. In the fifth Ti site, Ti(5) is bonded in a 7-coordinate geometry to one O(1), one O(15), one O(18), two equivalent O(3), and two equivalent O(7) atoms. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ho(2), one Ti(2), and one Ti(5) atom to form OHo2Ti2 tetrahedra that share  a cornercorner with one O(15)Ho2Ti2 tetrahedra,  a cornercorner with one O(19)Ho3Ti tetrahedra,  an edgeedge with one O(4)Ho3Ti tetrahedra, and  an edgeedge with one O(18)Ti4 trigonal pyramid. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ho(1), one Ho(2), and one Ti(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ho(2), one Ho(5), one Ti(3), and one Ti(5) atom. In the fourth O site, O(4) is bonded to one Ho(5), two equivalent Ho(2), and one Ti(4) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(16)Ho3Ti tetrahedra, corners with two equivalent O(17)Ho2Ti2 tetrahedra,  a cornercorner with one O(13)Ho3Ti trigonal pyramid,  an edgeedge with one O(1)Ho2Ti2 tetrahedra, and  an edgeedge with one O(9)Ho3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ho(4), one Ho(6), and one Ti(3) atom. In the sixth O site, O(6) is bonded to one Ho(3), two equivalent Ho(4), and one Ti(1) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(15)Ho2Ti2 tetrahedra, corners with two equivalent O(16)Ho3Ti tetrahedra, corners with three equivalent O(19)Ho3Ti tetrahedra, corners with four equivalent O(11)Ho4 tetrahedra, and edges with two equivalent O(17)Ho2Ti2 tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ho(1), one Ho(2), one Ho(5), and one Ti(5) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ho(5) and two equivalent Ti(3) atoms. In the ninth O site, O(9) is bonded to one Ho(5), two equivalent Ho(1), and one Ti(4) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(16)Ho3Ti tetrahedra, corners with two equivalent O(15)Ho2Ti2 tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra, corners with three equivalent O(13)Ho3Ti trigonal pyramids,  an edgeedge with one O(4)Ho3Ti tetrahedra, and edges with two equivalent O(17)Ho2Ti2 tetrahedra. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ho(2), one Ho(6), one Ti(2), and one Ti(3) atom. In the eleventh O site, O(11) is bonded to one Ho(1), one Ho(3), one Ho(4), and one Ho(7) atom to form OHo4 tetrahedra that share  a cornercorner with one O(14)Ho2Ti2 tetrahedra,  a cornercorner with one O(15)Ho2Ti2 tetrahedra,  a cornercorner with one O(9)Ho3Ti tetrahedra, corners with two equivalent O(16)Ho3Ti tetrahedra, corners with two equivalent O(6)Ho3Ti tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra,  an edgeedge with one O(17)Ho2Ti2 tetrahedra,  an edgeedge with one O(19)Ho3Ti tetrahedra, and  an edgeedge with one O(13)Ho3Ti trigonal pyramid. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Ho(3), one Ho(4), one Ho(7), and one Ti(3) atom. In the thirteenth O site, O(13) is bonded to one Ho(7), two equivalent Ho(1), and one Ti(4) atom to form distorted OHo3Ti trigonal pyramids that share  a cornercorner with one O(14)Ho2Ti2 tetrahedra,  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with three equivalent O(9)Ho3Ti tetrahedra, corners with four equivalent O(17)Ho2Ti2 tetrahedra,  an edgeedge with one O(15)Ho2Ti2 tetrahedra,  an edgeedge with one O(16)Ho3Ti tetrahedra, and edges with two equivalent O(11)Ho4 tetrahedra. In the fourteenth O site, O(14) is bonded to one Ho(6), one Ho(7), and two equivalent Ti(3) atoms to form OHo2Ti2 tetrahedra that share  a cornercorner with one O(16)Ho3Ti tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra,  a cornercorner with one O(13)Ho3Ti trigonal pyramid, and  an edgeedge with one O(18)Ti4 trigonal pyramid. In the fifteenth O site, O(15) is bonded to two equivalent Ho(1), one Ti(1), and one Ti(5) atom to form distorted OHo2Ti2 tetrahedra that share  a cornercorner with one O(1)Ho2Ti2 tetrahedra,  a cornercorner with one O(6)Ho3Ti tetrahedra, corners with two equivalent O(9)Ho3Ti tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra,  a cornercorner with one O(18)Ti4 trigonal pyramid, edges with two equivalent O(17)Ho2Ti2 tetrahedra, and  an edgeedge with one O(13)Ho3Ti trigonal pyramid. In the sixteenth O site, O(16) is bonded to one Ho(7), two equivalent Ho(4), and one Ti(4) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(14)Ho2Ti2 tetrahedra,  a cornercorner with one O(4)Ho3Ti tetrahedra,  a cornercorner with one O(9)Ho3Ti tetrahedra, corners with two equivalent O(6)Ho3Ti tetrahedra, corners with four equivalent O(11)Ho4 tetrahedra,  an edgeedge with one O(19)Ho3Ti tetrahedra, edges with two equivalent O(17)Ho2Ti2 tetrahedra, and  an edgeedge with one O(13)Ho3Ti trigonal pyramid. In the seventeenth O site, O(17) is bonded to one Ho(1), one Ho(4), one Ti(1), and one Ti(4) atom to form distorted OHo2Ti2 tetrahedra that share  a cornercorner with one O(19)Ho3Ti tetrahedra,  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with two equivalent O(17)Ho2Ti2 tetrahedra, corners with two equivalent O(13)Ho3Ti trigonal pyramids,  an edgeedge with one O(15)Ho2Ti2 tetrahedra,  an edgeedge with one O(16)Ho3Ti tetrahedra,  an edgeedge with one O(6)Ho3Ti tetrahedra,  an edgeedge with one O(9)Ho3Ti tetrahedra, and  an edgeedge with one O(11)Ho4 tetrahedra. In the eighteenth O site, O(18) is bonded to one Ti(2), one Ti(5), and two equivalent Ti(3) atoms to form OTi4 trigonal pyramids that share  a cornercorner with one O(15)Ho2Ti2 tetrahedra,  a cornercorner with one O(19)Ho3Ti tetrahedra,  an edgeedge with one O(1)Ho2Ti2 tetrahedra, and  an edgeedge with one O(14)Ho2Ti2 tetrahedra. In the nineteenth O site, O(19) is bonded to one Ho(3), two equivalent Ho(4), and one Ti(2) atom to form distorted OHo3Ti tetrahedra that share  a cornercorner with one O(1)Ho2Ti2 tetrahedra, corners with two equivalent O(17)Ho2Ti2 tetrahedra, corners with three equivalent O(6)Ho3Ti tetrahedra,  a cornercorner with one O(18)Ti4 trigonal pyramid,  an edgeedge with one O(16)Ho3Ti tetrahedra, and edges with two equivalent O(11)Ho4 tetrahedra.
Ho10Ti6O27 crystallizes in the monoclinic Cm space group. There are seven inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to one O(11), one O(13), one O(15), one O(17), one O(2), one O(7), and one O(9) atom to form distorted HoO7 pentagonal bipyramids that share  a cornercorner with one Ho(3)O6 octahedra,  a cornercorner with one Ho(1)O7 pentagonal bipyramid, and  an edgeedge with one Ho(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 71°. The Ho(1)-O(11) bond length is 2.29 Å. The Ho(1)-O(13) bond length is 2.43 Å. The Ho(1)-O(15) bond length is 2.39 Å. The Ho(1)-O(17) bond length is 2.33 Å. The Ho(1)-O(2) bond length is 2.33 Å. The Ho(1)-O(7) bond length is 2.42 Å. The Ho(1)-O(9) bond length is 2.17 Å. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), and one O(7) atom. The Ho(2)-O(1) bond length is 2.23 Å. The Ho(2)-O(10) bond length is 2.37 Å. The Ho(2)-O(2) bond length is 2.23 Å. The Ho(2)-O(3) bond length is 2.23 Å. The Ho(2)-O(4) bond length is 2.18 Å. The Ho(2)-O(7) bond length is 2.14 Å. In the third Ho site, Ho(3) is bonded to one O(19), one O(6), two equivalent O(11), and two equivalent O(12) atoms to form distorted corner-sharing HoO6 octahedra. The Ho(3)-O(19) bond length is 2.19 Å. The Ho(3)-O(6) bond length is 2.34 Å. Both Ho(3)-O(11) bond lengths are 2.39 Å. Both Ho(3)-O(12) bond lengths are 2.24 Å. In the fourth Ho site, Ho(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(16), one O(17), one O(19), one O(5), and one O(6) atom. The Ho(4)-O(11) bond length is 2.26 Å. The Ho(4)-O(12) bond length is 2.41 Å. The Ho(4)-O(16) bond length is 2.16 Å. The Ho(4)-O(17) bond length is 2.29 Å. The Ho(4)-O(19) bond length is 2.47 Å. The Ho(4)-O(5) bond length is 2.28 Å. The Ho(4)-O(6) bond length is 2.41 Å. In the fifth Ho site, Ho(5) is bonded in a 7-coordinate geometry to one O(4), one O(8), one O(9), two equivalent O(3), and two equivalent O(7) atoms. The Ho(5)-O(4) bond length is 2.20 Å. The Ho(5)-O(8) bond length is 2.28 Å. The Ho(5)-O(9) bond length is 2.28 Å. Both Ho(5)-O(3) bond lengths are 2.74 Å. Both Ho(5)-O(7) bond lengths are 2.10 Å. In the sixth Ho site, Ho(6) is bonded in a 3-coordinate geometry to one O(14), two equivalent O(10), and two equivalent O(5) atoms. The Ho(6)-O(14) bond length is 2.13 Å. Both Ho(6)-O(10) bond lengths are 2.61 Å. Both Ho(6)-O(5) bond lengths are 2.14 Å. In the seventh Ho site, Ho(7) is bonded in a 7-coordinate geometry to one O(13), one O(14), one O(16), two equivalent O(11), and two equivalent O(12) atoms. The Ho(7)-O(13) bond length is 2.45 Å. The Ho(7)-O(14) bond length is 2.31 Å. The Ho(7)-O(16) bond length is 2.15 Å. Both Ho(7)-O(11) bond lengths are 2.27 Å. Both Ho(7)-O(12) bond lengths are 2.51 Å. There are five inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(15), one O(6), two equivalent O(17), and two equivalent O(2) atoms. The Ti(1)-O(15) bond length is 2.07 Å. The Ti(1)-O(6) bond length is 1.93 Å. Both Ti(1)-O(17) bond lengths are 2.28 Å. Both Ti(1)-O(2) bond lengths are 1.86 Å. In the second Ti site, Ti(2) is bonded in a 5-coordinate geometry to one O(1), one O(18), one O(19), and two equivalent O(10) atoms. The Ti(2)-O(1) bond length is 2.07 Å. The Ti(2)-O(18) bond length is 2.06 Å. The Ti(2)-O(19) bond length is 1.89 Å. Both Ti(2)-O(10) bond lengths are 1.88 Å. In the third Ti site, Ti(3) is bonded in a 7-coordinate geometry to one O(10), one O(12), one O(14), one O(18), one O(3), one O(5), and one O(8) atom. The Ti(3)-O(10) bond length is 2.26 Å. The Ti(3)-O(12) bond length is 1.85 Å. The Ti(3)-O(14) bond length is 2.36 Å. The Ti(3)-O(18) bond length is 2.20 Å. The Ti(3)-O(3) bond length is 2.15 Å. The Ti(3)-O(5) bond length is 1.99 Å. The Ti(3)-O(8) bond length is 2.06 Å. In the fourth Ti site, Ti(4) is bonded in a 6-coordinate geometry to one O(13), one O(16), one O(4), one O(9), and two equivalent O(17) atoms. The Ti(4)-O(13) bond length is 1.98 Å. The Ti(4)-O(16) bond length is 2.07 Å. The Ti(4)-O(4) bond length is 2.03 Å. The Ti(4)-O(9) bond length is 2.21 Å. Both Ti(4)-O(17) bond lengths are 1.93 Å. In the fifth Ti site, Ti(5) is bonded in a 7-coordinate geometry to one O(1), one O(15), one O(18), two equivalent O(3), and two equivalent O(7) atoms. The Ti(5)-O(1) bond length is 1.93 Å. The Ti(5)-O(15) bond length is 2.07 Å. The Ti(5)-O(18) bond length is 2.07 Å. Both Ti(5)-O(3) bond lengths are 1.89 Å. Both Ti(5)-O(7) bond lengths are 2.54 Å. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ho(2), one Ti(2), and one Ti(5) atom to form OHo2Ti2 tetrahedra that share  a cornercorner with one O(15)Ho2Ti2 tetrahedra,  a cornercorner with one O(19)Ho3Ti tetrahedra,  an edgeedge with one O(4)Ho3Ti tetrahedra, and  an edgeedge with one O(18)Ti4 trigonal pyramid. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ho(1), one Ho(2), and one Ti(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ho(2), one Ho(5), one Ti(3), and one Ti(5) atom. In the fourth O site, O(4) is bonded to one Ho(5), two equivalent Ho(2), and one Ti(4) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(16)Ho3Ti tetrahedra, corners with two equivalent O(17)Ho2Ti2 tetrahedra,  a cornercorner with one O(13)Ho3Ti trigonal pyramid,  an edgeedge with one O(1)Ho2Ti2 tetrahedra, and  an edgeedge with one O(9)Ho3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ho(4), one Ho(6), and one Ti(3) atom. In the sixth O site, O(6) is bonded to one Ho(3), two equivalent Ho(4), and one Ti(1) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(15)Ho2Ti2 tetrahedra, corners with two equivalent O(16)Ho3Ti tetrahedra, corners with three equivalent O(19)Ho3Ti tetrahedra, corners with four equivalent O(11)Ho4 tetrahedra, and edges with two equivalent O(17)Ho2Ti2 tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ho(1), one Ho(2), one Ho(5), and one Ti(5) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ho(5) and two equivalent Ti(3) atoms. In the ninth O site, O(9) is bonded to one Ho(5), two equivalent Ho(1), and one Ti(4) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(16)Ho3Ti tetrahedra, corners with two equivalent O(15)Ho2Ti2 tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra, corners with three equivalent O(13)Ho3Ti trigonal pyramids,  an edgeedge with one O(4)Ho3Ti tetrahedra, and edges with two equivalent O(17)Ho2Ti2 tetrahedra. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ho(2), one Ho(6), one Ti(2), and one Ti(3) atom. In the eleventh O site, O(11) is bonded to one Ho(1), one Ho(3), one Ho(4), and one Ho(7) atom to form OHo4 tetrahedra that share  a cornercorner with one O(14)Ho2Ti2 tetrahedra,  a cornercorner with one O(15)Ho2Ti2 tetrahedra,  a cornercorner with one O(9)Ho3Ti tetrahedra, corners with two equivalent O(16)Ho3Ti tetrahedra, corners with two equivalent O(6)Ho3Ti tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra,  an edgeedge with one O(17)Ho2Ti2 tetrahedra,  an edgeedge with one O(19)Ho3Ti tetrahedra, and  an edgeedge with one O(13)Ho3Ti trigonal pyramid. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Ho(3), one Ho(4), one Ho(7), and one Ti(3) atom. In the thirteenth O site, O(13) is bonded to one Ho(7), two equivalent Ho(1), and one Ti(4) atom to form distorted OHo3Ti trigonal pyramids that share  a cornercorner with one O(14)Ho2Ti2 tetrahedra,  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with three equivalent O(9)Ho3Ti tetrahedra, corners with four equivalent O(17)Ho2Ti2 tetrahedra,  an edgeedge with one O(15)Ho2Ti2 tetrahedra,  an edgeedge with one O(16)Ho3Ti tetrahedra, and edges with two equivalent O(11)Ho4 tetrahedra. In the fourteenth O site, O(14) is bonded to one Ho(6), one Ho(7), and two equivalent Ti(3) atoms to form OHo2Ti2 tetrahedra that share  a cornercorner with one O(16)Ho3Ti tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra,  a cornercorner with one O(13)Ho3Ti trigonal pyramid, and  an edgeedge with one O(18)Ti4 trigonal pyramid. In the fifteenth O site, O(15) is bonded to two equivalent Ho(1), one Ti(1), and one Ti(5) atom to form distorted OHo2Ti2 tetrahedra that share  a cornercorner with one O(1)Ho2Ti2 tetrahedra,  a cornercorner with one O(6)Ho3Ti tetrahedra, corners with two equivalent O(9)Ho3Ti tetrahedra, corners with two equivalent O(11)Ho4 tetrahedra,  a cornercorner with one O(18)Ti4 trigonal pyramid, edges with two equivalent O(17)Ho2Ti2 tetrahedra, and  an edgeedge with one O(13)Ho3Ti trigonal pyramid. In the sixteenth O site, O(16) is bonded to one Ho(7), two equivalent Ho(4), and one Ti(4) atom to form OHo3Ti tetrahedra that share  a cornercorner with one O(14)Ho2Ti2 tetrahedra,  a cornercorner with one O(4)Ho3Ti tetrahedra,  a cornercorner with one O(9)Ho3Ti tetrahedra, corners with two equivalent O(6)Ho3Ti tetrahedra, corners with four equivalent O(11)Ho4 tetrahedra,  an edgeedge with one O(19)Ho3Ti tetrahedra, edges with two equivalent O(17)Ho2Ti2 tetrahedra, and  an edgeedge with one O(13)Ho3Ti trigonal pyramid. In the seventeenth O site, O(17) is bonded to one Ho(1), one Ho(4), one Ti(1), and one Ti(4) atom to form distorted OHo2Ti2 tetrahedra that share  a cornercorner with one O(19)Ho3Ti tetrahedra,  a cornercorner with one O(4)Ho3Ti tetrahedra, corners with two equivalent O(17)Ho2Ti2 tetrahedra, corners with two equivalent O(13)Ho3Ti trigonal pyramids,  an edgeedge with one O(15)Ho2Ti2 tetrahedra,  an edgeedge with one O(16)Ho3Ti tetrahedra,  an edgeedge with one O(6)Ho3Ti tetrahedra,  an edgeedge with one O(9)Ho3Ti tetrahedra, and  an edgeedge with one O(11)Ho4 tetrahedra. In the eighteenth O site, O(18) is bonded to one Ti(2), one Ti(5), and two equivalent Ti(3) atoms to form OTi4 trigonal pyramids that share  a cornercorner with one O(15)Ho2Ti2 tetrahedra,  a cornercorner with one O(19)Ho3Ti tetrahedra,  an edgeedge with one O(1)Ho2Ti2 tetrahedra, and  an edgeedge with one O(14)Ho2Ti2 tetrahedra. In the nineteenth O site, O(19) is bonded to one Ho(3), two equivalent Ho(4), and one Ti(2) atom to form distorted OHo3Ti tetrahedra that share  a cornercorner with one O(1)Ho2Ti2 tetrahedra, corners with two equivalent O(17)Ho2Ti2 tetrahedra, corners with three equivalent O(6)Ho3Ti tetrahedra,  a cornercorner with one O(18)Ti4 trigonal pyramid,  an edgeedge with one O(16)Ho3Ti tetrahedra, and edges with two equivalent O(11)Ho4 tetrahedra.