Sr4(Te3O8)Cl4 crystallizes in the monoclinic C2 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(7), two equivalent O(5), and one Cl(2) atom. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), two equivalent O(6), two equivalent O(7), two equivalent O(8), and one Cl(4) atom. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one Cl(2), one Cl(5), and two equivalent Cl(3) atoms. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one O(3), one O(4), one Cl(5), two equivalent Cl(3), and three equivalent Cl(1) atoms. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded in a rectangular see-saw-like geometry to one O(5), one O(6), one O(7), and one O(8) atom. In the second Te site, Te(2) is bonded in a distorted T-shaped geometry to one O(3), one O(4), and one O(5) atom. In the third Te site, Te(3) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Te(3) atom to form OSr3Te tetrahedra that share  a cornercorner with one O(6)Sr3Te tetrahedra, corners with two equivalent O(4)Sr3Te tetrahedra, corners with three equivalent O(7)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(3)Sr3Te tetrahedra,  an edgeedge with one O(6)Sr3Te tetrahedra, and edges with two equivalent O(2)Sr3Te tetrahedra. In the second O site, O(2) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Te(3) atom to form OSr3Te tetrahedra that share  a cornercorner with one O(7)Sr3Te tetrahedra, corners with two equivalent O(3)Sr3Te tetrahedra, corners with three equivalent O(6)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(4)Sr3Te tetrahedra,  an edgeedge with one O(7)Sr3Te tetrahedra, and edges with two equivalent O(1)Sr3Te tetrahedra. In the third O site, O(3) is bonded to one Sr(1), one Sr(3), one Sr(4), and one Te(2) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(6)Sr3Te tetrahedra,  a cornercorner with one O(7)Sr3Te tetrahedra, corners with two equivalent O(2)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(1)Sr3Te tetrahedra, edges with two equivalent O(4)Sr3Te tetrahedra, and  an edgeedge with one Cl(3)Sr4 trigonal pyramid. In the fourth O site, O(4) is bonded to one Sr(1), one Sr(3), one Sr(4), and one Te(2) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(6)Sr3Te tetrahedra,  a cornercorner with one O(7)Sr3Te tetrahedra, corners with two equivalent O(1)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(2)Sr3Te tetrahedra, edges with two equivalent O(3)Sr3Te tetrahedra, and  an edgeedge with one Cl(3)Sr4 trigonal pyramid. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Te(1), and one Te(2) atom. In the sixth O site, O(6) is bonded to one Sr(1), two equivalent Sr(2), and one Te(1) atom to form a mixture of corner and edge-sharing OSr3Te tetrahedra. In the seventh O site, O(7) is bonded to one Sr(1), two equivalent Sr(2), and one Te(1) atom to form a mixture of corner and edge-sharing OSr3Te tetrahedra. In the eighth O site, O(8) is bonded in a distorted linear geometry to two equivalent Sr(2), one Te(1), and one Te(3) atom. There are five inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 3-coordinate geometry to three equivalent Sr(4) atoms. In the second Cl site, Cl(2) is bonded in a linear geometry to one Sr(1) and one Sr(3) atom. In the third Cl site, Cl(3) is bonded to two equivalent Sr(3) and two equivalent Sr(4) atoms to form ClSr4 trigonal pyramids that share corners with two equivalent O(1)Sr3Te tetrahedra, corners with two equivalent O(2)Sr3Te tetrahedra, corners with two equivalent O(3)Sr3Te tetrahedra, corners with two equivalent O(4)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(3)Sr3Te tetrahedra,  an edgeedge with one O(4)Sr3Te tetrahedra, and  an edgeedge with one Cl(3)Sr4 trigonal pyramid. In the fourth Cl site, Cl(4) is bonded in a linear geometry to two equivalent Sr(2) atoms. In the fifth Cl site, Cl(5) is bonded in a 4-coordinate geometry to two equivalent Sr(3) and two equivalent Sr(4) atoms.
Sr4(Te3O8)Cl4 crystallizes in the monoclinic C2 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(7), two equivalent O(5), and one Cl(2) atom. The Sr(1)-O(1) bond length is 2.68 Å. The Sr(1)-O(2) bond length is 2.68 Å. The Sr(1)-O(3) bond length is 2.64 Å. The Sr(1)-O(4) bond length is 2.66 Å. The Sr(1)-O(6) bond length is 2.60 Å. The Sr(1)-O(7) bond length is 2.60 Å. There is one shorter (3.07 Å) and one longer (3.08 Å) Sr(1)-O(5) bond length. The Sr(1)-Cl(2) bond length is 3.05 Å. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), two equivalent O(6), two equivalent O(7), two equivalent O(8), and one Cl(4) atom. The Sr(2)-O(1) bond length is 2.66 Å. The Sr(2)-O(2) bond length is 2.65 Å. There is one shorter (2.56 Å) and one longer (2.68 Å) Sr(2)-O(6) bond length. There is one shorter (2.56 Å) and one longer (2.68 Å) Sr(2)-O(7) bond length. Both Sr(2)-O(8) bond lengths are 3.10 Å. The Sr(2)-Cl(4) bond length is 3.10 Å. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one Cl(2), one Cl(5), and two equivalent Cl(3) atoms. The Sr(3)-O(1) bond length is 2.53 Å. The Sr(3)-O(2) bond length is 2.54 Å. The Sr(3)-O(3) bond length is 2.76 Å. The Sr(3)-O(4) bond length is 2.76 Å. The Sr(3)-Cl(2) bond length is 3.12 Å. The Sr(3)-Cl(5) bond length is 2.96 Å. There is one shorter (3.07 Å) and one longer (3.17 Å) Sr(3)-Cl(3) bond length. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one O(3), one O(4), one Cl(5), two equivalent Cl(3), and three equivalent Cl(1) atoms. The Sr(4)-O(3) bond length is 2.49 Å. The Sr(4)-O(4) bond length is 2.52 Å. The Sr(4)-Cl(5) bond length is 3.41 Å. There is one shorter (2.99 Å) and one longer (3.27 Å) Sr(4)-Cl(3) bond length. There are a spread of Sr(4)-Cl(1) bond distances ranging from 2.90-3.31 Å. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded in a rectangular see-saw-like geometry to one O(5), one O(6), one O(7), and one O(8) atom. The Te(1)-O(5) bond length is 2.15 Å. The Te(1)-O(6) bond length is 1.88 Å. The Te(1)-O(7) bond length is 1.88 Å. The Te(1)-O(8) bond length is 2.15 Å. In the second Te site, Te(2) is bonded in a distorted T-shaped geometry to one O(3), one O(4), and one O(5) atom. The Te(2)-O(3) bond length is 1.89 Å. The Te(2)-O(4) bond length is 1.89 Å. The Te(2)-O(5) bond length is 1.93 Å. In the third Te site, Te(3) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(8) atom. The Te(3)-O(1) bond length is 1.88 Å. The Te(3)-O(2) bond length is 1.88 Å. The Te(3)-O(8) bond length is 1.92 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Te(3) atom to form OSr3Te tetrahedra that share  a cornercorner with one O(6)Sr3Te tetrahedra, corners with two equivalent O(4)Sr3Te tetrahedra, corners with three equivalent O(7)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(3)Sr3Te tetrahedra,  an edgeedge with one O(6)Sr3Te tetrahedra, and edges with two equivalent O(2)Sr3Te tetrahedra. In the second O site, O(2) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Te(3) atom to form OSr3Te tetrahedra that share  a cornercorner with one O(7)Sr3Te tetrahedra, corners with two equivalent O(3)Sr3Te tetrahedra, corners with three equivalent O(6)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(4)Sr3Te tetrahedra,  an edgeedge with one O(7)Sr3Te tetrahedra, and edges with two equivalent O(1)Sr3Te tetrahedra. In the third O site, O(3) is bonded to one Sr(1), one Sr(3), one Sr(4), and one Te(2) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(6)Sr3Te tetrahedra,  a cornercorner with one O(7)Sr3Te tetrahedra, corners with two equivalent O(2)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(1)Sr3Te tetrahedra, edges with two equivalent O(4)Sr3Te tetrahedra, and  an edgeedge with one Cl(3)Sr4 trigonal pyramid. In the fourth O site, O(4) is bonded to one Sr(1), one Sr(3), one Sr(4), and one Te(2) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(6)Sr3Te tetrahedra,  a cornercorner with one O(7)Sr3Te tetrahedra, corners with two equivalent O(1)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(2)Sr3Te tetrahedra, edges with two equivalent O(3)Sr3Te tetrahedra, and  an edgeedge with one Cl(3)Sr4 trigonal pyramid. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Te(1), and one Te(2) atom. In the sixth O site, O(6) is bonded to one Sr(1), two equivalent Sr(2), and one Te(1) atom to form a mixture of corner and edge-sharing OSr3Te tetrahedra. In the seventh O site, O(7) is bonded to one Sr(1), two equivalent Sr(2), and one Te(1) atom to form a mixture of corner and edge-sharing OSr3Te tetrahedra. In the eighth O site, O(8) is bonded in a distorted linear geometry to two equivalent Sr(2), one Te(1), and one Te(3) atom. There are five inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 3-coordinate geometry to three equivalent Sr(4) atoms. In the second Cl site, Cl(2) is bonded in a linear geometry to one Sr(1) and one Sr(3) atom. In the third Cl site, Cl(3) is bonded to two equivalent Sr(3) and two equivalent Sr(4) atoms to form ClSr4 trigonal pyramids that share corners with two equivalent O(1)Sr3Te tetrahedra, corners with two equivalent O(2)Sr3Te tetrahedra, corners with two equivalent O(3)Sr3Te tetrahedra, corners with two equivalent O(4)Sr3Te tetrahedra, corners with two equivalent Cl(3)Sr4 trigonal pyramids,  an edgeedge with one O(3)Sr3Te tetrahedra,  an edgeedge with one O(4)Sr3Te tetrahedra, and  an edgeedge with one Cl(3)Sr4 trigonal pyramid. In the fourth Cl site, Cl(4) is bonded in a linear geometry to two equivalent Sr(2) atoms. In the fifth Cl site, Cl(5) is bonded in a 4-coordinate geometry to two equivalent Sr(3) and two equivalent Sr(4) atoms.