Ni4(BiO2)9 crystallizes in the triclinic P1 space group. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted see-saw-like geometry to one O(14), one O(16), one O(18), and one O(3) atom. In the second Ni site, Ni(2) is bonded in a see-saw-like geometry to one O(18), one O(2), one O(4), and one O(6) atom. In the third Ni site, Ni(3) is bonded in a rectangular see-saw-like geometry to one O(10), one O(15), one O(6), and one O(8) atom. In the fourth Ni site, Ni(4) is bonded in a rectangular see-saw-like geometry to one O(1), one O(12), one O(13), and one O(15) atom. There are nine inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted see-saw-like geometry to one O(10), one O(16), one O(2), and one O(5) atom. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(10), one O(16), one O(17), one O(18), one O(4), and one O(7) atom. In the third Bi site, Bi(3) is bonded in a distorted rectangular see-saw-like geometry to one O(17), one O(2), one O(3), and one O(7) atom. In the fourth Bi site, Bi(4) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(9) atom to form distorted corner-sharing BiO5 square pyramids. In the fifth Bi site, Bi(5) is bonded in a 5-coordinate geometry to one O(12), one O(16), one O(6), one O(7), and one O(8) atom. In the sixth Bi site, Bi(6) is bonded in a 4-coordinate geometry to one O(11), one O(12), one O(13), and one O(5) atom. In the seventh Bi site, Bi(7) is bonded in a 6-coordinate geometry to one O(13), one O(14), one O(17), one O(18), one O(5), and one O(9) atom. In the eighth Bi site, Bi(8) is bonded to one O(11), one O(14), one O(15), one O(7), and one O(9) atom to form a mixture of distorted corner and edge-sharing BiO5 square pyramids. In the ninth Bi site, Bi(9) is bonded to one O(1), one O(11), one O(14), one O(17), and one O(8) atom to form a mixture of corner and edge-sharing BiO5 square pyramids. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ni(4), one Bi(4), and one Bi(9) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ni(2), one Bi(1), and one Bi(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ni(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 Ni(2), one Bi(2), and one Bi(4) atom. In the fifth O site, O(5) is bonded to one Bi(1), one Bi(4), one Bi(6), and one Bi(7) atom to form distorted OBi4 trigonal pyramids that share  a cornercorner with one O(17)Bi4 tetrahedra,  a cornercorner with one O(18)Ni2Bi2 tetrahedra, and  a cornercorner with one O(16)NiBi3 tetrahedra. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ni(2), one Ni(3), and one Bi(5) atom. In the seventh O site, O(7) is bonded to one Bi(2), one Bi(3), one Bi(5), and one Bi(8) atom to form distorted OBi4 trigonal pyramids that share  a cornercorner with one O(18)Ni2Bi2 tetrahedra,  an edgeedge with one O(17)Bi4 tetrahedra, and  an edgeedge with one O(16)NiBi3 tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Ni(3), one Bi(5), and one Bi(9) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Bi(4), one Bi(7), and one Bi(8) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Ni(3), one Bi(1), and one Bi(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Bi(6), one Bi(8), and one Bi(9) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Ni(4), one Bi(5), and one Bi(6) atom. In the thirteenth O site, O(13) is bonded in a trigonal non-coplanar geometry to one Ni(4), one Bi(6), and one Bi(7) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ni(1), one Bi(7), one Bi(8), and one Bi(9) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ni(3), one Ni(4), and one Bi(8) atom. In the sixteenth O site, O(16) is bonded to one Ni(1), one Bi(1), one Bi(2), and one Bi(5) atom to form distorted ONiBi3 tetrahedra that share  a cornercorner with one O(17)Bi4 tetrahedra,  a cornercorner with one O(5)Bi4 trigonal pyramid,  an edgeedge with one O(18)Ni2Bi2 tetrahedra, and  an edgeedge with one O(7)Bi4 trigonal pyramid. In the seventeenth O site, O(17) is bonded to one Bi(2), one Bi(3), one Bi(7), and one Bi(9) atom to form OBi4 tetrahedra that share  a cornercorner with one O(16)NiBi3 tetrahedra,  a cornercorner with one O(5)Bi4 trigonal pyramid,  an edgeedge with one O(18)Ni2Bi2 tetrahedra, and  an edgeedge with one O(7)Bi4 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Ni(1), one Ni(2), one Bi(2), and one Bi(7) atom to form distorted ONi2Bi2 tetrahedra that share  a cornercorner with one O(5)Bi4 trigonal pyramid,  a cornercorner with one O(7)Bi4 trigonal pyramid,  an edgeedge with one O(17)Bi4 tetrahedra, and  an edgeedge with one O(16)NiBi3 tetrahedra.
Ni4(BiO2)9 crystallizes in the triclinic P1 space group. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted see-saw-like geometry to one O(14), one O(16), one O(18), and one O(3) atom. The Ni(1)-O(14) bond length is 1.95 Å. The Ni(1)-O(16) bond length is 1.99 Å. The Ni(1)-O(18) bond length is 2.02 Å. The Ni(1)-O(3) bond length is 1.94 Å. In the second Ni site, Ni(2) is bonded in a see-saw-like geometry to one O(18), one O(2), one O(4), and one O(6) atom. The Ni(2)-O(18) bond length is 1.96 Å. The Ni(2)-O(2) bond length is 1.98 Å. The Ni(2)-O(4) bond length is 1.95 Å. The Ni(2)-O(6) bond length is 1.93 Å. In the third Ni site, Ni(3) is bonded in a rectangular see-saw-like geometry to one O(10), one O(15), one O(6), and one O(8) atom. The Ni(3)-O(10) bond length is 1.93 Å. The Ni(3)-O(15) bond length is 2.04 Å. The Ni(3)-O(6) bond length is 1.95 Å. The Ni(3)-O(8) bond length is 2.09 Å. In the fourth Ni site, Ni(4) is bonded in a rectangular see-saw-like geometry to one O(1), one O(12), one O(13), and one O(15) atom. The Ni(4)-O(1) bond length is 1.95 Å. The Ni(4)-O(12) bond length is 1.96 Å. The Ni(4)-O(13) bond length is 2.05 Å. The Ni(4)-O(15) bond length is 1.92 Å. There are nine inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted see-saw-like geometry to one O(10), one O(16), one O(2), and one O(5) atom. The Bi(1)-O(10) bond length is 2.10 Å. The Bi(1)-O(16) bond length is 2.29 Å. The Bi(1)-O(2) bond length is 2.39 Å. The Bi(1)-O(5) bond length is 2.15 Å. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(10), one O(16), one O(17), one O(18), one O(4), and one O(7) atom. The Bi(2)-O(10) bond length is 2.73 Å. The Bi(2)-O(16) bond length is 2.26 Å. The Bi(2)-O(17) bond length is 2.39 Å. The Bi(2)-O(18) bond length is 2.37 Å. The Bi(2)-O(4) bond length is 2.36 Å. The Bi(2)-O(7) bond length is 2.74 Å. In the third Bi site, Bi(3) is bonded in a distorted rectangular see-saw-like geometry to one O(17), one O(2), one O(3), and one O(7) atom. The Bi(3)-O(17) bond length is 2.32 Å. The Bi(3)-O(2) bond length is 2.12 Å. The Bi(3)-O(3) bond length is 2.66 Å. The Bi(3)-O(7) bond length is 2.19 Å. In the fourth Bi site, Bi(4) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(9) atom to form distorted corner-sharing BiO5 square pyramids. The Bi(4)-O(1) bond length is 2.28 Å. The Bi(4)-O(3) bond length is 2.09 Å. The Bi(4)-O(4) bond length is 2.20 Å. The Bi(4)-O(5) bond length is 2.60 Å. The Bi(4)-O(9) bond length is 2.33 Å. In the fifth Bi site, Bi(5) is bonded in a 5-coordinate geometry to one O(12), one O(16), one O(6), one O(7), and one O(8) atom. The Bi(5)-O(12) bond length is 2.12 Å. The Bi(5)-O(16) bond length is 2.72 Å. The Bi(5)-O(6) bond length is 2.20 Å. The Bi(5)-O(7) bond length is 2.58 Å. The Bi(5)-O(8) bond length is 2.24 Å. In the sixth Bi site, Bi(6) is bonded in a 4-coordinate geometry to one O(11), one O(12), one O(13), and one O(5) atom. The Bi(6)-O(11) bond length is 2.09 Å. The Bi(6)-O(12) bond length is 2.21 Å. The Bi(6)-O(13) bond length is 2.21 Å. The Bi(6)-O(5) bond length is 2.50 Å. In the seventh Bi site, Bi(7) is bonded in a 6-coordinate geometry to one O(13), one O(14), one O(17), one O(18), one O(5), and one O(9) atom. The Bi(7)-O(13) bond length is 2.15 Å. The Bi(7)-O(14) bond length is 2.56 Å. The Bi(7)-O(17) bond length is 2.43 Å. The Bi(7)-O(18) bond length is 2.30 Å. The Bi(7)-O(5) bond length is 2.34 Å. The Bi(7)-O(9) bond length is 2.44 Å. In the eighth Bi site, Bi(8) is bonded to one O(11), one O(14), one O(15), one O(7), and one O(9) atom to form a mixture of distorted corner and edge-sharing BiO5 square pyramids. The Bi(8)-O(11) bond length is 2.42 Å. The Bi(8)-O(14) bond length is 2.48 Å. The Bi(8)-O(15) bond length is 2.34 Å. The Bi(8)-O(7) bond length is 2.27 Å. The Bi(8)-O(9) bond length is 2.12 Å. In the ninth Bi site, Bi(9) is bonded to one O(1), one O(11), one O(14), one O(17), and one O(8) atom to form a mixture of corner and edge-sharing BiO5 square pyramids. The Bi(9)-O(1) bond length is 2.45 Å. The Bi(9)-O(11) bond length is 2.30 Å. The Bi(9)-O(14) bond length is 2.31 Å. The Bi(9)-O(17) bond length is 2.48 Å. The Bi(9)-O(8) bond length is 2.13 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ni(4), one Bi(4), and one Bi(9) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ni(2), one Bi(1), and one Bi(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ni(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 Ni(2), one Bi(2), and one Bi(4) atom. In the fifth O site, O(5) is bonded to one Bi(1), one Bi(4), one Bi(6), and one Bi(7) atom to form distorted OBi4 trigonal pyramids that share  a cornercorner with one O(17)Bi4 tetrahedra,  a cornercorner with one O(18)Ni2Bi2 tetrahedra, and  a cornercorner with one O(16)NiBi3 tetrahedra. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ni(2), one Ni(3), and one Bi(5) atom. In the seventh O site, O(7) is bonded to one Bi(2), one Bi(3), one Bi(5), and one Bi(8) atom to form distorted OBi4 trigonal pyramids that share  a cornercorner with one O(18)Ni2Bi2 tetrahedra,  an edgeedge with one O(17)Bi4 tetrahedra, and  an edgeedge with one O(16)NiBi3 tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Ni(3), one Bi(5), and one Bi(9) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Bi(4), one Bi(7), and one Bi(8) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Ni(3), one Bi(1), and one Bi(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Bi(6), one Bi(8), and one Bi(9) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Ni(4), one Bi(5), and one Bi(6) atom. In the thirteenth O site, O(13) is bonded in a trigonal non-coplanar geometry to one Ni(4), one Bi(6), and one Bi(7) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ni(1), one Bi(7), one Bi(8), and one Bi(9) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ni(3), one Ni(4), and one Bi(8) atom. In the sixteenth O site, O(16) is bonded to one Ni(1), one Bi(1), one Bi(2), and one Bi(5) atom to form distorted ONiBi3 tetrahedra that share  a cornercorner with one O(17)Bi4 tetrahedra,  a cornercorner with one O(5)Bi4 trigonal pyramid,  an edgeedge with one O(18)Ni2Bi2 tetrahedra, and  an edgeedge with one O(7)Bi4 trigonal pyramid. In the seventeenth O site, O(17) is bonded to one Bi(2), one Bi(3), one Bi(7), and one Bi(9) atom to form OBi4 tetrahedra that share  a cornercorner with one O(16)NiBi3 tetrahedra,  a cornercorner with one O(5)Bi4 trigonal pyramid,  an edgeedge with one O(18)Ni2Bi2 tetrahedra, and  an edgeedge with one O(7)Bi4 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Ni(1), one Ni(2), one Bi(2), and one Bi(7) atom to form distorted ONi2Bi2 tetrahedra that share  a cornercorner with one O(5)Bi4 trigonal pyramid,  a cornercorner with one O(7)Bi4 trigonal pyramid,  an edgeedge with one O(17)Bi4 tetrahedra, and  an edgeedge with one O(16)NiBi3 tetrahedra.