Fe3B7O13I crystallizes in the trigonal R3c space group. Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(4), one O(5), and two equivalent I(1) atoms. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form corner-sharing BO4 tetrahedra. In the third B site, B(3) is bonded in a trigonal planar geometry to three equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to three equivalent B(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(1), one B(1), and one B(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(1), one B(1), and one B(3) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(1), one B(1), and one B(2) atom. I(1) is bonded to six equivalent Fe(1) atoms to form distorted corner-sharing IFe6 octahedra. The corner-sharing octahedral tilt angles are 2°.
Fe3B7O13I crystallizes in the trigonal R3c space group. Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(4), one O(5), and two equivalent I(1) atoms. The Fe(1)-O(2) bond length is 2.14 Å. The Fe(1)-O(3) bond length is 2.16 Å. The Fe(1)-O(4) bond length is 2.07 Å. The Fe(1)-O(5) bond length is 2.00 Å. There is one shorter (2.81 Å) and one longer (3.31 Å) Fe(1)-I(1) bond length. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing BO4 tetrahedra. The B(1)-O(2) bond length is 1.45 Å. The B(1)-O(3) bond length is 1.45 Å. The B(1)-O(4) bond length is 1.51 Å. The B(1)-O(5) bond length is 1.48 Å. In the second B site, B(2) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form corner-sharing BO4 tetrahedra. The B(2)-O(1) bond length is 1.56 Å. The B(2)-O(2) bond length is 1.44 Å. The B(2)-O(3) bond length is 1.45 Å. The B(2)-O(5) bond length is 1.48 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to three equivalent O(4) atoms. All B(3)-O(4) bond lengths are 1.38 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to three equivalent B(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(1), one B(1), and one B(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(1), one B(1), and one B(3) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(1), one B(1), and one B(2) atom. I(1) is bonded to six equivalent Fe(1) atoms to form distorted corner-sharing IFe6 octahedra. The corner-sharing octahedral tilt angles are 2°.