Co2Bi11O20 crystallizes in the triclinic P1 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(13), one O(2), one O(5), and one O(8) atom to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid, and  a cornercorner with one Co(2)O4 tetrahedra. In the second Co site, Co(2) is bonded to one O(18), one O(19), one O(2), and one O(7) atom to form CoO4 tetrahedra that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid, and  a cornercorner with one Co(1)O5 trigonal bipyramid. There are eleven inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(16), one O(20), one O(3), and one O(4) atom. In the second Bi site, Bi(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(20), one O(5), and one O(6) atom. In the third Bi site, Bi(3) is bonded to one O(11), one O(13), one O(19), one O(3), and one O(6) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra, and  a cornercorner with one Co(1)O5 trigonal bipyramid. In the fourth Bi site, Bi(4) is bonded in a 5-coordinate geometry to one O(18), one O(3), one O(4), one O(5), and one O(9) atom. In the fifth Bi site, Bi(5) is bonded to one O(10), one O(15), one O(4), one O(7), and one O(8) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra, and  a cornercorner with one Co(1)O5 trigonal bipyramid. In the sixth Bi site, Bi(6) is bonded in a 5-coordinate geometry to one O(11), one O(12), one O(2), one O(6), and one O(9) atom. In the seventh Bi site, Bi(7) is bonded to one O(12), one O(13), one O(14), one O(17), and one O(7) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid, and  an edgeedge with one Bi(10)O5 square pyramid. In the eighth Bi site, Bi(8) is bonded in a 5-coordinate geometry to one O(10), one O(17), one O(18), one O(20), and one O(8) atom. In the ninth Bi site, Bi(9) is bonded to one O(10), one O(14), one O(16), one O(19), and one O(9) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid, and  a cornercorner with one Co(2)O4 tetrahedra. In the tenth Bi site, Bi(10) is bonded to one O(1), one O(12), one O(15), one O(17), and one O(19) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid, and  an edgeedge with one Bi(7)O5 square pyramid. In the eleventh Bi site, Bi(11) is bonded in a 5-coordinate geometry to one O(11), one O(14), one O(15), one O(16), and one O(18) atom. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(1), one Bi(10), and one Bi(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Co(1), one Co(2), and one Bi(6) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(3), and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(4), and one Bi(5) atom. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Co(1), one Bi(2), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Bi(2), one Bi(3), and one Bi(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Co(2), one Bi(5), and one Bi(7) atom. In the eighth O site, O(8) is bonded in a 1-coordinate geometry to one Co(1), one Bi(5), and one Bi(8) atom. In the ninth O site, O(9) is bonded in a trigonal non-coplanar geometry to one Bi(4), one Bi(6), and one Bi(9) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Bi(5), one Bi(8), and one Bi(9) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Bi(11), one Bi(3), and one Bi(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Bi(10), one Bi(6), and one Bi(7) atom. In the thirteenth O site, O(13) is bonded in a trigonal non-coplanar geometry to one Co(1), one Bi(3), and one Bi(7) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal non-coplanar geometry to one Bi(11), one Bi(7), and one Bi(9) atom. In the fifteenth O site, O(15) is bonded in a trigonal planar geometry to one Bi(10), one Bi(11), and one Bi(5) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Bi(1), one Bi(11), and one Bi(9) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal non-coplanar geometry to one Bi(10), one Bi(7), and one Bi(8) atom. In the eighteenth O site, O(18) is bonded in a distorted single-bond geometry to one Co(2), one Bi(11), one Bi(4), and one Bi(8) atom. In the nineteenth O site, O(19) is bonded in a distorted tetrahedral geometry to one Co(2), one Bi(10), one Bi(3), and one Bi(9) atom. In the twentieth O site, O(20) is bonded in a trigonal planar geometry to one Bi(1), one Bi(2), and one Bi(8) atom.
Co2Bi11O20 crystallizes in the triclinic P1 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(13), one O(2), one O(5), and one O(8) atom to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid, and  a cornercorner with one Co(2)O4 tetrahedra. The Co(1)-O(1) bond length is 2.16 Å. The Co(1)-O(13) bond length is 2.03 Å. The Co(1)-O(2) bond length is 2.20 Å. The Co(1)-O(5) bond length is 1.99 Å. The Co(1)-O(8) bond length is 1.78 Å. In the second Co site, Co(2) is bonded to one O(18), one O(19), one O(2), and one O(7) atom to form CoO4 tetrahedra that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid, and  a cornercorner with one Co(1)O5 trigonal bipyramid. The Co(2)-O(18) bond length is 1.82 Å. The Co(2)-O(19) bond length is 1.82 Å. The Co(2)-O(2) bond length is 1.84 Å. The Co(2)-O(7) bond length is 1.82 Å. There are eleven inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(16), one O(20), one O(3), and one O(4) atom. The Bi(1)-O(16) bond length is 2.12 Å. The Bi(1)-O(20) bond length is 2.24 Å. The Bi(1)-O(3) bond length is 2.16 Å. The Bi(1)-O(4) bond length is 2.57 Å. In the second Bi site, Bi(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(20), one O(5), and one O(6) atom. The Bi(2)-O(1) bond length is 2.21 Å. The Bi(2)-O(20) bond length is 2.34 Å. The Bi(2)-O(5) bond length is 2.38 Å. The Bi(2)-O(6) bond length is 2.12 Å. In the third Bi site, Bi(3) is bonded to one O(11), one O(13), one O(19), one O(3), and one O(6) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra, and  a cornercorner with one Co(1)O5 trigonal bipyramid. The Bi(3)-O(11) bond length is 2.27 Å. The Bi(3)-O(13) bond length is 2.22 Å. The Bi(3)-O(19) bond length is 2.54 Å. The Bi(3)-O(3) bond length is 2.11 Å. The Bi(3)-O(6) bond length is 2.59 Å. In the fourth Bi site, Bi(4) is bonded in a 5-coordinate geometry to one O(18), one O(3), one O(4), one O(5), and one O(9) atom. The Bi(4)-O(18) bond length is 2.58 Å. The Bi(4)-O(3) bond length is 2.55 Å. The Bi(4)-O(4) bond length is 2.30 Å. The Bi(4)-O(5) bond length is 2.11 Å. The Bi(4)-O(9) bond length is 2.26 Å. In the fifth Bi site, Bi(5) is bonded to one O(10), one O(15), one O(4), one O(7), and one O(8) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra, and  a cornercorner with one Co(1)O5 trigonal bipyramid. The Bi(5)-O(10) bond length is 2.68 Å. The Bi(5)-O(15) bond length is 2.25 Å. The Bi(5)-O(4) bond length is 2.10 Å. The Bi(5)-O(7) bond length is 2.47 Å. The Bi(5)-O(8) bond length is 2.32 Å. In the sixth Bi site, Bi(6) is bonded in a 5-coordinate geometry to one O(11), one O(12), one O(2), one O(6), and one O(9) atom. The Bi(6)-O(11) bond length is 2.70 Å. The Bi(6)-O(12) bond length is 2.08 Å. The Bi(6)-O(2) bond length is 2.76 Å. The Bi(6)-O(6) bond length is 2.21 Å. The Bi(6)-O(9) bond length is 2.22 Å. In the seventh Bi site, Bi(7) is bonded to one O(12), one O(13), one O(14), one O(17), and one O(7) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid, and  an edgeedge with one Bi(10)O5 square pyramid. The Bi(7)-O(12) bond length is 2.51 Å. The Bi(7)-O(13) bond length is 2.24 Å. The Bi(7)-O(14) bond length is 2.13 Å. The Bi(7)-O(17) bond length is 2.25 Å. The Bi(7)-O(7) bond length is 2.57 Å. In the eighth Bi site, Bi(8) is bonded in a 5-coordinate geometry to one O(10), one O(17), one O(18), one O(20), and one O(8) atom. The Bi(8)-O(10) bond length is 2.23 Å. The Bi(8)-O(17) bond length is 2.10 Å. The Bi(8)-O(18) bond length is 2.70 Å. The Bi(8)-O(20) bond length is 2.19 Å. The Bi(8)-O(8) bond length is 2.69 Å. In the ninth Bi site, Bi(9) is bonded to one O(10), one O(14), one O(16), one O(19), and one O(9) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(10)O5 square pyramid,  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(7)O5 square pyramid, and  a cornercorner with one Co(2)O4 tetrahedra. The Bi(9)-O(10) bond length is 2.12 Å. The Bi(9)-O(14) bond length is 2.27 Å. The Bi(9)-O(16) bond length is 2.68 Å. The Bi(9)-O(19) bond length is 2.57 Å. The Bi(9)-O(9) bond length is 2.25 Å. In the tenth Bi site, Bi(10) is bonded to one O(1), one O(12), one O(15), one O(17), and one O(19) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Bi(3)O5 square pyramid,  a cornercorner with one Bi(5)O5 square pyramid,  a cornercorner with one Bi(9)O5 square pyramid,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid, and  an edgeedge with one Bi(7)O5 square pyramid. The Bi(10)-O(1) bond length is 2.12 Å. The Bi(10)-O(12) bond length is 2.20 Å. The Bi(10)-O(15) bond length is 2.26 Å. The Bi(10)-O(17) bond length is 2.66 Å. The Bi(10)-O(19) bond length is 2.63 Å. In the eleventh Bi site, Bi(11) is bonded in a 5-coordinate geometry to one O(11), one O(14), one O(15), one O(16), and one O(18) atom. The Bi(11)-O(11) bond length is 2.11 Å. The Bi(11)-O(14) bond length is 2.57 Å. The Bi(11)-O(15) bond length is 2.24 Å. The Bi(11)-O(16) bond length is 2.23 Å. The Bi(11)-O(18) bond length is 2.84 Å. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(1), one Bi(10), and one Bi(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Co(1), one Co(2), and one Bi(6) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(3), and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(4), and one Bi(5) atom. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Co(1), one Bi(2), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Bi(2), one Bi(3), and one Bi(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Co(2), one Bi(5), and one Bi(7) atom. In the eighth O site, O(8) is bonded in a 1-coordinate geometry to one Co(1), one Bi(5), and one Bi(8) atom. In the ninth O site, O(9) is bonded in a trigonal non-coplanar geometry to one Bi(4), one Bi(6), and one Bi(9) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Bi(5), one Bi(8), and one Bi(9) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Bi(11), one Bi(3), and one Bi(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Bi(10), one Bi(6), and one Bi(7) atom. In the thirteenth O site, O(13) is bonded in a trigonal non-coplanar geometry to one Co(1), one Bi(3), and one Bi(7) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal non-coplanar geometry to one Bi(11), one Bi(7), and one Bi(9) atom. In the fifteenth O site, O(15) is bonded in a trigonal planar geometry to one Bi(10), one Bi(11), and one Bi(5) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Bi(1), one Bi(11), and one Bi(9) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal non-coplanar geometry to one Bi(10), one Bi(7), and one Bi(8) atom. In the eighteenth O site, O(18) is bonded in a distorted single-bond geometry to one Co(2), one Bi(11), one Bi(4), and one Bi(8) atom. In the nineteenth O site, O(19) is bonded in a distorted tetrahedral geometry to one Co(2), one Bi(10), one Bi(3), and one Bi(9) atom. In the twentieth O site, O(20) is bonded in a trigonal planar geometry to one Bi(1), one Bi(2), and one Bi(8) atom.