Y4Si3O11F2 crystallizes in the triclinic P-1 space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(4), one O(6), one O(7), one O(9), one F(1), and one F(2) atom. In the second Y site, Y(2) is bonded to one O(3), one O(7), two equivalent O(1), two equivalent O(2), and one F(1) atom to form distorted YO6F pentagonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, edges with two equivalent Y(2)O6F pentagonal bipyramids, and  an edgeedge with one Si(1)O4 tetrahedra. In the third Y site, Y(3) is bonded to one O(11), one O(5), two equivalent O(10), two equivalent O(8), and one F(2) atom to form distorted YO6F pentagonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(3)O4 tetrahedra, edges with two equivalent Y(3)O6F pentagonal bipyramids, and  an edgeedge with one Si(3)O4 tetrahedra. In the fourth Y site, Y(4) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(5), one O(6), one O(9), one F(1), and one F(2) atom. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with three equivalent Y(2)O6F pentagonal bipyramids,  a cornercorner with one Si(2)O4 tetrahedra, and  an edgeedge with one Y(2)O6F pentagonal bipyramid. In the second Si site, Si(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Y(2)O6F pentagonal bipyramid,  a cornercorner with one Y(3)O6F pentagonal bipyramid, and  a cornercorner with one Si(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(10), one O(11), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with three equivalent Y(3)O6F pentagonal bipyramids and  an edgeedge with one Y(3)O6F pentagonal bipyramid. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Y(1), two equivalent Y(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Y(2) and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Y(1), one Y(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Y(1), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Y(3), one Y(4), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(4), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(2), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Y(3) and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(4), and one Si(3) atom. In the tenth O site, O(10) is bonded to one Y(4), two equivalent Y(3), and one Si(3) atom to form distorted edge-sharing OY3Si tetrahedra. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Y(3), one Y(4), and one Si(3) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Y(1), one Y(2), and one Y(4) atom. In the second F site, F(2) is bonded in a distorted trigonal non-coplanar geometry to one Y(1), one Y(3), and one Y(4) atom.
Y4Si3O11F2 crystallizes in the triclinic P-1 space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(4), one O(6), one O(7), one O(9), one F(1), and one F(2) atom. The Y(1)-O(1) bond length is 2.56 Å. The Y(1)-O(3) bond length is 2.29 Å. The Y(1)-O(4) bond length is 2.89 Å. The Y(1)-O(6) bond length is 2.28 Å. The Y(1)-O(7) bond length is 2.35 Å. The Y(1)-O(9) bond length is 2.39 Å. The Y(1)-F(1) bond length is 2.37 Å. The Y(1)-F(2) bond length is 2.38 Å. In the second Y site, Y(2) is bonded to one O(3), one O(7), two equivalent O(1), two equivalent O(2), and one F(1) atom to form distorted YO6F pentagonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, edges with two equivalent Y(2)O6F pentagonal bipyramids, and  an edgeedge with one Si(1)O4 tetrahedra. The Y(2)-O(3) bond length is 2.45 Å. The Y(2)-O(7) bond length is 2.31 Å. There is one shorter (2.35 Å) and one longer (2.38 Å) Y(2)-O(1) bond length. There is one shorter (2.24 Å) and one longer (2.32 Å) Y(2)-O(2) bond length. The Y(2)-F(1) bond length is 2.26 Å. In the third Y site, Y(3) is bonded to one O(11), one O(5), two equivalent O(10), two equivalent O(8), and one F(2) atom to form distorted YO6F pentagonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(3)O4 tetrahedra, edges with two equivalent Y(3)O6F pentagonal bipyramids, and  an edgeedge with one Si(3)O4 tetrahedra. The Y(3)-O(11) bond length is 2.41 Å. The Y(3)-O(5) bond length is 2.26 Å. There is one shorter (2.33 Å) and one longer (2.43 Å) Y(3)-O(10) bond length. There is one shorter (2.29 Å) and one longer (2.31 Å) Y(3)-O(8) bond length. The Y(3)-F(2) bond length is 2.35 Å. In the fourth Y site, Y(4) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(5), one O(6), one O(9), one F(1), and one F(2) atom. The Y(4)-O(10) bond length is 2.33 Å. The Y(4)-O(11) bond length is 2.29 Å. The Y(4)-O(5) bond length is 2.40 Å. The Y(4)-O(6) bond length is 2.26 Å. The Y(4)-O(9) bond length is 2.30 Å. The Y(4)-F(1) bond length is 2.26 Å. The Y(4)-F(2) bond length is 2.42 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with three equivalent Y(2)O6F pentagonal bipyramids,  a cornercorner with one Si(2)O4 tetrahedra, and  an edgeedge with one Y(2)O6F pentagonal bipyramid. The Si(1)-O(1) bond length is 1.68 Å. The Si(1)-O(2) bond length is 1.64 Å. The Si(1)-O(3) bond length is 1.64 Å. The Si(1)-O(4) bond length is 1.65 Å. In the second Si site, Si(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Y(2)O6F pentagonal bipyramid,  a cornercorner with one Y(3)O6F pentagonal bipyramid, and  a cornercorner with one Si(1)O4 tetrahedra. The Si(2)-O(4) bond length is 1.67 Å. The Si(2)-O(5) bond length is 1.64 Å. The Si(2)-O(6) bond length is 1.64 Å. The Si(2)-O(7) bond length is 1.64 Å. In the third Si site, Si(3) is bonded to one O(10), one O(11), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with three equivalent Y(3)O6F pentagonal bipyramids and  an edgeedge with one Y(3)O6F pentagonal bipyramid. The Si(3)-O(10) bond length is 1.70 Å. The Si(3)-O(11) bond length is 1.64 Å. The Si(3)-O(8) bond length is 1.66 Å. The Si(3)-O(9) bond length is 1.64 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Y(1), two equivalent Y(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Y(2) and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Y(1), one Y(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Y(1), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Y(3), one Y(4), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(4), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(2), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Y(3) and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(4), and one Si(3) atom. In the tenth O site, O(10) is bonded to one Y(4), two equivalent Y(3), and one Si(3) atom to form distorted edge-sharing OY3Si tetrahedra. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Y(3), one Y(4), and one Si(3) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Y(1), one Y(2), and one Y(4) atom. In the second F site, F(2) is bonded in a distorted trigonal non-coplanar geometry to one Y(1), one Y(3), and one Y(4) atom.