Y4Ti13Si2(SbO14)2 crystallizes in the monoclinic C2/m space group. Y(1) is bonded to one O(1), one O(5), and three equivalent O(2) atoms to form distorted YO5 square pyramids that share corners with two equivalent Y(1)O5 square pyramids,  a cornercorner with one Ti(2)O5 trigonal bipyramid, corners with three equivalent Ti(1)O5 trigonal bipyramids, edges with two equivalent Y(1)O5 square pyramids, and  an edgeedge with one Ti(1)O5 trigonal bipyramid. There are five inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(7), one O(8), and two equivalent O(1) atoms to form distorted TiO5 trigonal bipyramids that share corners with three equivalent Y(1)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Ti(2)O5 trigonal bipyramids,  an edgeedge with one Y(1)O5 square pyramid,  an edgeedge with one Ti(1)O5 trigonal bipyramid, and  an edgeedge with one Ti(2)O5 trigonal bipyramid. In the second Ti site, Ti(2) is bonded to one O(1), one O(3), one O(6), and two equivalent O(7) atoms to form distorted TiO5 trigonal bipyramids that share  a cornercorner with one Ti(4)O6 octahedra,  a cornercorner with one Y(1)O5 square pyramid, corners with three equivalent Si(1)O4 tetrahedra,  a cornercorner with one Ti(2)O5 trigonal bipyramid, corners with two equivalent Ti(1)O5 trigonal bipyramids,  an edgeedge with one Ti(1)O5 trigonal bipyramid, and  an edgeedge with one Ti(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 61°. In the third Ti site, Ti(3) is bonded in a 6-coordinate geometry to two equivalent O(8) and four equivalent O(5) atoms. In the fourth Ti site, Ti(4) is bonded to two equivalent O(4) and four equivalent O(6) atoms to form distorted TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with four equivalent Ti(2)O5 trigonal bipyramids. In the fifth Ti site, Ti(5) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms. Si(1) is bonded to one O(3), one O(4), and two equivalent O(7) atoms to form SiO4 tetrahedra that share  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(1)O5 trigonal bipyramids, and corners with six equivalent Ti(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 61°. Sb(1) is bonded in a 4-coordinate geometry to two equivalent O(5) and two equivalent O(6) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Y(1), one Ti(2), and two equivalent Ti(1) atoms to form distorted OYTi3 trigonal pyramids that share corners with three equivalent O(2)Y3Ti tetrahedra,  a cornercorner with one O(5)YTi2Sb trigonal pyramid,  an edgeedge with one O(2)Y3Ti tetrahedra, and  an edgeedge with one O(1)YTi3 trigonal pyramid. In the second O site, O(2) is bonded to three equivalent Y(1) and one Ti(1) atom to form distorted OY3Ti tetrahedra that share corners with two equivalent O(2)Y3Ti tetrahedra, corners with three equivalent O(5)YTi2Sb trigonal pyramids, corners with three equivalent O(1)YTi3 trigonal pyramids, edges with two equivalent O(2)Y3Ti tetrahedra, and  an edgeedge with one O(1)YTi3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Ti(2) and one Si(1) atom. In the fourth O site, O(4) is bonded to one Ti(4), two equivalent Ti(5), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OTi3Si tetrahedra. In the fifth O site, O(5) is bonded to one Y(1), two equivalent Ti(3), and one Sb(1) atom to form OYTi2Sb trigonal pyramids that share corners with three equivalent O(2)Y3Ti tetrahedra,  a cornercorner with one O(1)YTi3 trigonal pyramid, corners with three equivalent O(5)YTi2Sb trigonal pyramids, and edges with two equivalent O(5)YTi2Sb trigonal pyramids. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(4), one Ti(5), and one Sb(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ti(1), two equivalent Ti(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ti(1), one Ti(3), and one Ti(5) atom.
Y4Ti13Si2(SbO14)2 crystallizes in the monoclinic C2/m space group. Y(1) is bonded to one O(1), one O(5), and three equivalent O(2) atoms to form distorted YO5 square pyramids that share corners with two equivalent Y(1)O5 square pyramids,  a cornercorner with one Ti(2)O5 trigonal bipyramid, corners with three equivalent Ti(1)O5 trigonal bipyramids, edges with two equivalent Y(1)O5 square pyramids, and  an edgeedge with one Ti(1)O5 trigonal bipyramid. The Y(1)-O(1) bond length is 2.19 Å. The Y(1)-O(5) bond length is 2.19 Å. There are a spread of Y(1)-O(2) bond distances ranging from 2.30-2.37 Å. There are five inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(7), one O(8), and two equivalent O(1) atoms to form distorted TiO5 trigonal bipyramids that share corners with three equivalent Y(1)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Ti(2)O5 trigonal bipyramids,  an edgeedge with one Y(1)O5 square pyramid,  an edgeedge with one Ti(1)O5 trigonal bipyramid, and  an edgeedge with one Ti(2)O5 trigonal bipyramid. The Ti(1)-O(2) bond length is 1.92 Å. The Ti(1)-O(7) bond length is 1.99 Å. The Ti(1)-O(8) bond length is 1.87 Å. There is one shorter (1.96 Å) and one longer (2.28 Å) Ti(1)-O(1) bond length. In the second Ti site, Ti(2) is bonded to one O(1), one O(3), one O(6), and two equivalent O(7) atoms to form distorted TiO5 trigonal bipyramids that share  a cornercorner with one Ti(4)O6 octahedra,  a cornercorner with one Y(1)O5 square pyramid, corners with three equivalent Si(1)O4 tetrahedra,  a cornercorner with one Ti(2)O5 trigonal bipyramid, corners with two equivalent Ti(1)O5 trigonal bipyramids,  an edgeedge with one Ti(1)O5 trigonal bipyramid, and  an edgeedge with one Ti(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 61°. The Ti(2)-O(1) bond length is 2.08 Å. The Ti(2)-O(3) bond length is 2.05 Å. The Ti(2)-O(6) bond length is 2.07 Å. There is one shorter (2.08 Å) and one longer (2.48 Å) Ti(2)-O(7) bond length. In the third Ti site, Ti(3) is bonded in a 6-coordinate geometry to two equivalent O(8) and four equivalent O(5) atoms. Both Ti(3)-O(8) bond lengths are 2.12 Å. There are two shorter (2.13 Å) and two longer (2.15 Å) Ti(3)-O(5) bond lengths. In the fourth Ti site, Ti(4) is bonded to two equivalent O(4) and four equivalent O(6) atoms to form distorted TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with four equivalent Ti(2)O5 trigonal bipyramids. Both Ti(4)-O(4) bond lengths are 2.35 Å. All Ti(4)-O(6) bond lengths are 2.09 Å. In the fifth Ti site, Ti(5) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms. Both Ti(5)-O(4) bond lengths are 2.22 Å. Both Ti(5)-O(6) bond lengths are 2.19 Å. Both Ti(5)-O(8) bond lengths are 2.06 Å. Si(1) is bonded to one O(3), one O(4), and two equivalent O(7) atoms to form SiO4 tetrahedra that share  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(1)O5 trigonal bipyramids, and corners with six equivalent Ti(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 61°. The Si(1)-O(3) bond length is 1.62 Å. The Si(1)-O(4) bond length is 1.65 Å. Both Si(1)-O(7) bond lengths are 1.65 Å. Sb(1) is bonded in a 4-coordinate geometry to two equivalent O(5) and two equivalent O(6) atoms. Both Sb(1)-O(5) bond lengths are 2.33 Å. Both Sb(1)-O(6) bond lengths are 2.64 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Y(1), one Ti(2), and two equivalent Ti(1) atoms to form distorted OYTi3 trigonal pyramids that share corners with three equivalent O(2)Y3Ti tetrahedra,  a cornercorner with one O(5)YTi2Sb trigonal pyramid,  an edgeedge with one O(2)Y3Ti tetrahedra, and  an edgeedge with one O(1)YTi3 trigonal pyramid. In the second O site, O(2) is bonded to three equivalent Y(1) and one Ti(1) atom to form distorted OY3Ti tetrahedra that share corners with two equivalent O(2)Y3Ti tetrahedra, corners with three equivalent O(5)YTi2Sb trigonal pyramids, corners with three equivalent O(1)YTi3 trigonal pyramids, edges with two equivalent O(2)Y3Ti tetrahedra, and  an edgeedge with one O(1)YTi3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Ti(2) and one Si(1) atom. In the fourth O site, O(4) is bonded to one Ti(4), two equivalent Ti(5), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OTi3Si tetrahedra. In the fifth O site, O(5) is bonded to one Y(1), two equivalent Ti(3), and one Sb(1) atom to form OYTi2Sb trigonal pyramids that share corners with three equivalent O(2)Y3Ti tetrahedra,  a cornercorner with one O(1)YTi3 trigonal pyramid, corners with three equivalent O(5)YTi2Sb trigonal pyramids, and edges with two equivalent O(5)YTi2Sb trigonal pyramids. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(4), one Ti(5), and one Sb(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ti(1), two equivalent Ti(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ti(1), one Ti(3), and one Ti(5) atom.