B10Bi6O21 crystallizes in the triclinic P-1 space group. There are five inequivalent B sites. In the first B site, B(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(9) atom. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(11), one O(5), and one O(8) atom. In the fourth B site, B(4) is bonded to one O(10), one O(11), one O(6), and one O(9) atom to form corner-sharing BO4 tetrahedra. In the fifth B site, B(5) is bonded in a trigonal planar geometry to one O(10), one O(2), and one O(7) atom. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(6), and two equivalent O(7) atoms. In the second Bi site, Bi(2) is bonded in a distorted bent 150 degrees geometry to one O(1) and one O(5) atom. In the third Bi site, Bi(3) is bonded in a water-like geometry to one O(3) and one O(8) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one B(2), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent B(5) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to one B(1) and one Bi(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one B(1) and one B(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one B(1), one B(3), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one B(1), one B(4), and one Bi(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one B(5) and two equivalent Bi(1) atoms. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one B(3) and one Bi(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one B(2) and one B(4) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one B(4) and one B(5) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one B(3) and one B(4) atom.
B10Bi6O21 crystallizes in the triclinic P-1 space group. There are five inequivalent B sites. In the first B site, B(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing BO4 tetrahedra. The B(1)-O(3) bond length is 1.42 Å. The B(1)-O(4) bond length is 1.48 Å. The B(1)-O(5) bond length is 1.55 Å. The B(1)-O(6) bond length is 1.48 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(9) atom. The B(2)-O(1) bond length is 1.40 Å. The B(2)-O(4) bond length is 1.38 Å. The B(2)-O(9) bond length is 1.38 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(11), one O(5), and one O(8) atom. The B(3)-O(11) bond length is 1.38 Å. The B(3)-O(5) bond length is 1.41 Å. The B(3)-O(8) bond length is 1.37 Å. In the fourth B site, B(4) is bonded to one O(10), one O(11), one O(6), and one O(9) atom to form corner-sharing BO4 tetrahedra. The B(4)-O(10) bond length is 1.44 Å. The B(4)-O(11) bond length is 1.48 Å. The B(4)-O(6) bond length is 1.51 Å. The B(4)-O(9) bond length is 1.49 Å. In the fifth B site, B(5) is bonded in a trigonal planar geometry to one O(10), one O(2), and one O(7) atom. The B(5)-O(10) bond length is 1.37 Å. The B(5)-O(2) bond length is 1.37 Å. The B(5)-O(7) bond length is 1.40 Å. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(6), and two equivalent O(7) atoms. The Bi(1)-O(1) bond length is 2.15 Å. The Bi(1)-O(6) bond length is 2.21 Å. There is one shorter (2.27 Å) and one longer (2.44 Å) Bi(1)-O(7) bond length. In the second Bi site, Bi(2) is bonded in a distorted bent 150 degrees geometry to one O(1) and one O(5) atom. The Bi(2)-O(1) bond length is 2.68 Å. The Bi(2)-O(5) bond length is 2.40 Å. In the third Bi site, Bi(3) is bonded in a water-like geometry to one O(3) and one O(8) atom. The Bi(3)-O(3) bond length is 2.23 Å. The Bi(3)-O(8) bond length is 2.22 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one B(2), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent B(5) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to one B(1) and one Bi(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one B(1) and one B(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one B(1), one B(3), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one B(1), one B(4), and one Bi(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one B(5) and two equivalent Bi(1) atoms. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one B(3) and one Bi(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one B(2) and one B(4) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one B(4) and one B(5) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one B(3) and one B(4) atom.