Bi4Ti3O12 crystallizes in the monoclinic Cc space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(10) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 21-30°. In the second Ti site, Ti(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 25-35°. In the third Ti site, Ti(3) is bonded in a 6-coordinate geometry to one O(2), one O(6), two equivalent O(11), and two equivalent O(9) atoms. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to two equivalent O(12), two equivalent O(5), and two equivalent O(8) atoms. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to two equivalent O(12), two equivalent O(2), and two equivalent O(5) atoms. In the third Bi site, Bi(3) is bonded in a 6-coordinate geometry to one O(10), one O(11), two equivalent O(6), and two equivalent O(9) atoms. In the fourth Bi site, Bi(4) is bonded in a 8-coordinate geometry to one O(10), one O(3), two equivalent O(1), two equivalent O(4), and two equivalent O(7) atoms. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ti(1) and two equivalent Bi(4) atoms. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ti(3) and two equivalent Bi(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ti(2) and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(2), and two equivalent Bi(4) atoms. In the fifth O site, O(5) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(3), and two equivalent Bi(3) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ti(2) and two equivalent Bi(4) atoms. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Ti(2) and two equivalent Bi(1) atoms. In the ninth O site, O(9) is bonded to two equivalent Ti(3) and two equivalent Bi(3) atoms to form distorted edge-sharing OTi2Bi2 tetrahedra. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent Ti(1), one Bi(3), and one Bi(4) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to two equivalent Ti(3) and one Bi(3) atom. In the twelfth O site, O(12) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra.
Bi4Ti3O12 crystallizes in the monoclinic Cc space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(10) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 21-30°. The Ti(1)-O(4) bond length is 2.00 Å. The Ti(1)-O(6) bond length is 1.97 Å. There is one shorter (1.85 Å) and one longer (2.07 Å) Ti(1)-O(1) bond length. There is one shorter (1.86 Å) and one longer (2.07 Å) Ti(1)-O(10) bond length. In the second Ti site, Ti(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 25-35°. The Ti(2)-O(4) bond length is 2.29 Å. The Ti(2)-O(8) bond length is 1.78 Å. There is one shorter (1.90 Å) and one longer (2.02 Å) Ti(2)-O(3) bond length. There is one shorter (1.94 Å) and one longer (2.09 Å) Ti(2)-O(7) bond length. In the third Ti site, Ti(3) is bonded in a 6-coordinate geometry to one O(2), one O(6), two equivalent O(11), and two equivalent O(9) atoms. The Ti(3)-O(2) bond length is 1.75 Å. The Ti(3)-O(6) bond length is 2.46 Å. There is one shorter (1.92 Å) and one longer (2.01 Å) Ti(3)-O(11) bond length. There is one shorter (1.96 Å) and one longer (2.05 Å) Ti(3)-O(9) bond length. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to two equivalent O(12), two equivalent O(5), and two equivalent O(8) atoms. There is one shorter (2.27 Å) and one longer (2.43 Å) Bi(1)-O(12) bond length. There is one shorter (2.21 Å) and one longer (2.38 Å) Bi(1)-O(5) bond length. There is one shorter (2.49 Å) and one longer (2.56 Å) Bi(1)-O(8) bond length. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to two equivalent O(12), two equivalent O(2), and two equivalent O(5) atoms. There is one shorter (2.25 Å) and one longer (2.33 Å) Bi(2)-O(12) bond length. There is one shorter (2.62 Å) and one longer (2.70 Å) Bi(2)-O(2) bond length. There is one shorter (2.21 Å) and one longer (2.35 Å) Bi(2)-O(5) bond length. In the third Bi site, Bi(3) is bonded in a 6-coordinate geometry to one O(10), one O(11), two equivalent O(6), and two equivalent O(9) atoms. The Bi(3)-O(10) bond length is 2.43 Å. The Bi(3)-O(11) bond length is 2.30 Å. There is one shorter (2.29 Å) and one longer (2.39 Å) Bi(3)-O(6) bond length. There is one shorter (2.36 Å) and one longer (2.51 Å) Bi(3)-O(9) bond length. In the fourth Bi site, Bi(4) is bonded in a 8-coordinate geometry to one O(10), one O(3), two equivalent O(1), two equivalent O(4), and two equivalent O(7) atoms. The Bi(4)-O(10) bond length is 2.74 Å. The Bi(4)-O(3) bond length is 2.35 Å. There is one shorter (2.63 Å) and one longer (2.64 Å) Bi(4)-O(1) bond length. There is one shorter (2.30 Å) and one longer (2.35 Å) Bi(4)-O(4) bond length. There is one shorter (2.41 Å) and one longer (2.44 Å) Bi(4)-O(7) bond length. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ti(1) and two equivalent Bi(4) atoms. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ti(3) and two equivalent Bi(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ti(2) and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(2), and two equivalent Bi(4) atoms. In the fifth O site, O(5) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Ti(1), one Ti(3), and two equivalent Bi(3) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ti(2) and two equivalent Bi(4) atoms. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Ti(2) and two equivalent Bi(1) atoms. In the ninth O site, O(9) is bonded to two equivalent Ti(3) and two equivalent Bi(3) atoms to form distorted edge-sharing OTi2Bi2 tetrahedra. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent Ti(1), one Bi(3), and one Bi(4) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to two equivalent Ti(3) and one Bi(3) atom. In the twelfth O site, O(12) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra.