Al4Sn13Si2(SbO14)2 crystallizes in the monoclinic C2/m space group. Al(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form AlO4 tetrahedra that share  a cornercorner with one Sb(1)O6 octahedra and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. There are five inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 3-coordinate geometry to one O(2), one O(8), and two equivalent O(1) atoms. In the second Sn site, Sn(2) is bonded in a distorted T-shaped geometry to one O(3), one O(6), and one O(7) atom. In the third Sn site, Sn(3) is bonded in a rectangular see-saw-like geometry to two equivalent O(5) and two equivalent O(8) atoms. In the fourth Sn site, Sn(4) is bonded in a distorted linear geometry to two equivalent O(4) atoms. In the fifth Sn site, Sn(5) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms to form distorted SnO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Sn(5)O6 octahedra, and edges with two equivalent Sb(1)O6 octahedra. Si(1) is bonded to one O(3), one O(4), and two equivalent O(7) atoms to form SiO4 tetrahedra that share corners with two equivalent Sn(5)O6 octahedra. The corner-sharing octahedral tilt angles are 61°. Sb(1) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(8) atoms to form SbO6 octahedra that share corners with two equivalent Al(1)O4 tetrahedra and edges with two equivalent Sn(5)O6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Al(1) and two equivalent Sn(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Al(1) and one Sn(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Sn(2) and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sn(4), two equivalent Sn(5), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Al(1), one Sn(3), and one Sb(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Sn(2), one Sn(5), and one Sb(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Sn(2) and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Sn(1), one Sn(3), one Sn(5), and one Sb(1) atom.
Al4Sn13Si2(SbO14)2 crystallizes in the monoclinic C2/m space group. Al(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form AlO4 tetrahedra that share  a cornercorner with one Sb(1)O6 octahedra and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. The Al(1)-O(1) bond length is 1.77 Å. The Al(1)-O(5) bond length is 1.78 Å. There is one shorter (1.81 Å) and one longer (1.82 Å) Al(1)-O(2) bond length. There are five inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 3-coordinate geometry to one O(2), one O(8), and two equivalent O(1) atoms. The Sn(1)-O(2) bond length is 2.31 Å. The Sn(1)-O(8) bond length is 2.77 Å. There is one shorter (2.15 Å) and one longer (2.28 Å) Sn(1)-O(1) bond length. In the second Sn site, Sn(2) is bonded in a distorted T-shaped geometry to one O(3), one O(6), and one O(7) atom. The Sn(2)-O(3) bond length is 2.31 Å. The Sn(2)-O(6) bond length is 2.21 Å. The Sn(2)-O(7) bond length is 2.14 Å. In the third Sn site, Sn(3) is bonded in a rectangular see-saw-like geometry to two equivalent O(5) and two equivalent O(8) atoms. Both Sn(3)-O(5) bond lengths are 2.37 Å. Both Sn(3)-O(8) bond lengths are 2.21 Å. In the fourth Sn site, Sn(4) is bonded in a distorted linear geometry to two equivalent O(4) atoms. Both Sn(4)-O(4) bond lengths are 2.39 Å. In the fifth Sn site, Sn(5) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms to form distorted SnO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Sn(5)O6 octahedra, and edges with two equivalent Sb(1)O6 octahedra. Both Sn(5)-O(4) bond lengths are 2.51 Å. Both Sn(5)-O(6) bond lengths are 2.43 Å. Both Sn(5)-O(8) bond lengths are 2.53 Å. Si(1) is bonded to one O(3), one O(4), and two equivalent O(7) atoms to form SiO4 tetrahedra that share corners with two equivalent Sn(5)O6 octahedra. The corner-sharing octahedral tilt angles are 61°. The Si(1)-O(3) bond length is 1.71 Å. The Si(1)-O(4) bond length is 1.65 Å. Both Si(1)-O(7) bond lengths are 1.64 Å. Sb(1) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(8) atoms to form SbO6 octahedra that share corners with two equivalent Al(1)O4 tetrahedra and edges with two equivalent Sn(5)O6 octahedra. Both Sb(1)-O(5) bond lengths are 2.03 Å. Both Sb(1)-O(6) bond lengths are 2.08 Å. Both Sb(1)-O(8) bond lengths are 2.00 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Al(1) and two equivalent Sn(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Al(1) and one Sn(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Sn(2) and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sn(4), two equivalent Sn(5), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Al(1), one Sn(3), and one Sb(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Sn(2), one Sn(5), and one Sb(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Sn(2) and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Sn(1), one Sn(3), one Sn(5), and one Sb(1) atom.