Ba3SnFe10O20 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to two equivalent O(5) and four equivalent O(4) atoms. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Sn(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with three equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-67°. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(2)O4 tetrahedra, and corners with three equivalent Fe(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the third Fe site, Fe(3) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O4 tetrahedra, corners with four equivalent Fe(1)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Sn(1)O6 octahedra. Sn(1) is bonded to two equivalent O(3) and four equivalent O(6) atoms to form SnO6 octahedra that share corners with four equivalent Fe(1)O4 tetrahedra and edges with four equivalent Fe(3)O6 octahedra. There are six inequivalent O sites. In the first O site, O(2) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(3) atom. In the second O site, O(3) is bonded to one Ba(2), two equivalent Fe(3), and one Sn(1) atom to form distorted OBaFe2Sn tetrahedra that share  a cornercorner with one O(3)BaFe2Sn tetrahedra, corners with two equivalent O(4)Ba2Fe2 tetrahedra, and  an edgeedge with one O(3)BaFe2Sn tetrahedra. In the third O site, O(4) is bonded to one Ba(1), one Ba(2), one Fe(1), and one Fe(2) atom to form distorted OBa2Fe2 tetrahedra that share  a cornercorner with one O(3)BaFe2Sn tetrahedra, corners with two equivalent O(4)Ba2Fe2 tetrahedra, and  an edgeedge with one O(4)Ba2Fe2 tetrahedra. In the fourth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ba(1) and two equivalent Fe(2) atoms. In the fifth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), one Fe(3), and one Sn(1) atom. In the sixth O site, O(1) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), and one Fe(2) atom.
Ba3SnFe10O20 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to two equivalent O(5) and four equivalent O(4) atoms. Both Ba(1)-O(5) bond lengths are 2.67 Å. All Ba(1)-O(4) bond lengths are 2.84 Å. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms. The Ba(2)-O(3) bond length is 2.64 Å. Both Ba(2)-O(1) bond lengths are 2.82 Å. Both Ba(2)-O(4) bond lengths are 2.80 Å. Both Ba(2)-O(6) bond lengths are 3.11 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Sn(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with three equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-67°. The Fe(1)-O(1) bond length is 1.88 Å. The Fe(1)-O(2) bond length is 1.93 Å. The Fe(1)-O(4) bond length is 1.90 Å. The Fe(1)-O(6) bond length is 1.91 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(2)O4 tetrahedra, and corners with three equivalent Fe(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. The Fe(2)-O(1) bond length is 1.88 Å. The Fe(2)-O(2) bond length is 1.94 Å. The Fe(2)-O(4) bond length is 1.91 Å. The Fe(2)-O(5) bond length is 1.89 Å. In the third Fe site, Fe(3) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O4 tetrahedra, corners with four equivalent Fe(1)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Sn(1)O6 octahedra. Both Fe(3)-O(2) bond lengths are 1.99 Å. Both Fe(3)-O(3) bond lengths are 2.02 Å. Both Fe(3)-O(6) bond lengths are 1.99 Å. Sn(1) is bonded to two equivalent O(3) and four equivalent O(6) atoms to form SnO6 octahedra that share corners with four equivalent Fe(1)O4 tetrahedra and edges with four equivalent Fe(3)O6 octahedra. Both Sn(1)-O(3) bond lengths are 2.06 Å. All Sn(1)-O(6) bond lengths are 2.10 Å. There are six inequivalent O sites. In the first O site, O(2) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(3) atom. In the second O site, O(3) is bonded to one Ba(2), two equivalent Fe(3), and one Sn(1) atom to form distorted OBaFe2Sn tetrahedra that share  a cornercorner with one O(3)BaFe2Sn tetrahedra, corners with two equivalent O(4)Ba2Fe2 tetrahedra, and  an edgeedge with one O(3)BaFe2Sn tetrahedra. In the third O site, O(4) is bonded to one Ba(1), one Ba(2), one Fe(1), and one Fe(2) atom to form distorted OBa2Fe2 tetrahedra that share  a cornercorner with one O(3)BaFe2Sn tetrahedra, corners with two equivalent O(4)Ba2Fe2 tetrahedra, and  an edgeedge with one O(4)Ba2Fe2 tetrahedra. In the fourth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ba(1) and two equivalent Fe(2) atoms. In the fifth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), one Fe(3), and one Sn(1) atom. In the sixth O site, O(1) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), and one Fe(2) atom.