SrTiFe4Bi4O15 crystallizes in the monoclinic Cm space group. Sr(1) is bonded to two equivalent O(6), two equivalent O(8), four equivalent O(4), and four equivalent O(5) atoms to form distorted SrO12 cuboctahedra that share corners with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Ti(1)O6 octahedra, and faces with four equivalent Fe(1)O6 octahedra. Ti(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(8) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-15°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and faces with two equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 10-18°. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(7) atoms to form distorted corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 16-18°. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 3-coordinate geometry to one O(1), one O(5), and one O(6) atom. In the second Bi site, Bi(2) is bonded in a 3-coordinate geometry to one O(2), one O(3), and one O(7) atom. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 1-coordinate geometry to two equivalent Sr(1) and two equivalent Ti(1) atoms. In the second O site, O(1) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Bi(1) atom. In the third O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Bi(2) atom. In the fourth O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Fe(2) and one Bi(2) atom. In the fifth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Fe(1) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Ti(1), one Fe(1), and one Bi(1) atom. In the seventh O site, O(6) is bonded in a 4-coordinate geometry to one Sr(1), two equivalent Fe(1), and one Bi(1) atom. In the eighth O site, O(7) is bonded in a distorted T-shaped geometry to two equivalent Fe(2) and one Bi(2) atom.
SrTiFe4Bi4O15 crystallizes in the monoclinic Cm space group. Sr(1) is bonded to two equivalent O(6), two equivalent O(8), four equivalent O(4), and four equivalent O(5) atoms to form distorted SrO12 cuboctahedra that share corners with two equivalent Sr(1)O12 cuboctahedra, faces with two equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Ti(1)O6 octahedra, and faces with four equivalent Fe(1)O6 octahedra. Both Sr(1)-O(6) bond lengths are 2.81 Å. There is one shorter (2.82 Å) and one longer (2.96 Å) Sr(1)-O(8) bond length. There are two shorter (2.67 Å) and two longer (2.89 Å) Sr(1)-O(4) bond lengths. There are two shorter (2.74 Å) and two longer (3.20 Å) Sr(1)-O(5) bond lengths. Ti(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(8) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-15°. Both Ti(1)-O(4) bond lengths are 1.95 Å. Both Ti(1)-O(5) bond lengths are 2.02 Å. There is one shorter (1.81 Å) and one longer (2.26 Å) Ti(1)-O(8) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and faces with two equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 10-18°. The Fe(1)-O(1) bond length is 2.18 Å. The Fe(1)-O(2) bond length is 1.96 Å. The Fe(1)-O(4) bond length is 1.94 Å. The Fe(1)-O(5) bond length is 2.14 Å. There is one shorter (1.97 Å) and one longer (2.15 Å) Fe(1)-O(6) bond length. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(7) atoms to form distorted corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 16-18°. The Fe(2)-O(1) bond length is 1.96 Å. The Fe(2)-O(2) bond length is 2.14 Å. There is one shorter (1.96 Å) and one longer (2.13 Å) Fe(2)-O(3) bond length. There is one shorter (1.96 Å) and one longer (2.15 Å) Fe(2)-O(7) bond length. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 3-coordinate geometry to one O(1), one O(5), and one O(6) atom. The Bi(1)-O(1) bond length is 2.20 Å. The Bi(1)-O(5) bond length is 2.25 Å. The Bi(1)-O(6) bond length is 2.23 Å. In the second Bi site, Bi(2) is bonded in a 3-coordinate geometry to one O(2), one O(3), and one O(7) atom. The Bi(2)-O(2) bond length is 2.20 Å. The Bi(2)-O(3) bond length is 2.23 Å. The Bi(2)-O(7) bond length is 2.21 Å. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 1-coordinate geometry to two equivalent Sr(1) and two equivalent Ti(1) atoms. In the second O site, O(1) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Bi(1) atom. In the third O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Bi(2) atom. In the fourth O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Fe(2) and one Bi(2) atom. In the fifth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Fe(1) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Ti(1), one Fe(1), and one Bi(1) atom. In the seventh O site, O(6) is bonded in a 4-coordinate geometry to one Sr(1), two equivalent Fe(1), and one Bi(1) atom. In the eighth O site, O(7) is bonded in a distorted T-shaped geometry to two equivalent Fe(2) and one Bi(2) atom.