V8O15 crystallizes in the triclinic P-1 space group. There are eight inequivalent V sites. In the first V site, V(1) is bonded to one O(14), one O(15), one O(6), one O(7), one O(8), and one O(9) atom to form a mixture of distorted corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-62°. In the second V site, V(2) is bonded in a 6-coordinate geometry to one O(15), one O(4), one O(6), one O(9), and two equivalent O(5) atoms. In the third V site, V(3) is bonded to one O(1), one O(10), one O(3), one O(8), and two equivalent O(12) atoms to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. In the fourth V site, V(4) is bonded to one O(1), one O(10), one O(13), one O(2), and two equivalent O(3) atoms to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. In the fifth V site, V(5) is bonded to one O(11), one O(15), one O(5), one O(6), and two equivalent O(9) atoms to form a mixture of distorted corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. In the sixth V site, V(6) is bonded to one O(10), one O(11), one O(13), one O(14), one O(2), and one O(8) atom to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. In the seventh V site, V(7) is bonded to one O(1), one O(12), one O(14), one O(2), one O(4), and one O(7) atom to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the eighth V site, V(8) is bonded to one O(11), one O(13), one O(4), one O(5), one O(6), and one O(7) atom to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-62°. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one V(3), one V(4), and one V(7) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one V(4), one V(6), and one V(7) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one V(3) and two equivalent V(4) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one V(2), one V(7), and one V(8) atom. In the fifth O site, O(5) is bonded to one V(5), one V(8), and two equivalent V(2) atoms to form a mixture of distorted corner and edge-sharing OV4 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one V(1), one V(2), one V(5), and one V(8) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one V(1), one V(7), and one V(8) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one V(1), one V(3), and one V(6) atom. In the ninth O site, O(9) is bonded to one V(1), one V(2), and two equivalent V(5) atoms to form a mixture of distorted corner and edge-sharing OV4 trigonal pyramids. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one V(3), one V(4), and one V(6) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one V(5), one V(6), and one V(8) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one V(7) and two equivalent V(3) atoms. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one V(4), one V(6), and one V(8) atom. In the fourteenth O site, O(14) is bonded in a trigonal planar geometry to one V(1), one V(6), and one V(7) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one V(1), one V(2), and one V(5) atom.
V8O15 crystallizes in the triclinic P-1 space group. There are eight inequivalent V sites. In the first V site, V(1) is bonded to one O(14), one O(15), one O(6), one O(7), one O(8), and one O(9) atom to form a mixture of distorted corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-62°. The V(1)-O(14) bond length is 1.91 Å. The V(1)-O(15) bond length is 2.21 Å. The V(1)-O(6) bond length is 2.12 Å. The V(1)-O(7) bond length is 1.92 Å. The V(1)-O(8) bond length is 1.77 Å. The V(1)-O(9) bond length is 2.07 Å. In the second V site, V(2) is bonded in a 6-coordinate geometry to one O(15), one O(4), one O(6), one O(9), and two equivalent O(5) atoms. The V(2)-O(15) bond length is 1.77 Å. The V(2)-O(4) bond length is 1.90 Å. The V(2)-O(6) bond length is 2.16 Å. The V(2)-O(9) bond length is 1.99 Å. There is one shorter (2.00 Å) and one longer (2.18 Å) V(2)-O(5) bond length. In the third V site, V(3) is bonded to one O(1), one O(10), one O(3), one O(8), and two equivalent O(12) atoms to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. The V(3)-O(1) bond length is 1.93 Å. The V(3)-O(10) bond length is 1.96 Å. The V(3)-O(3) bond length is 1.89 Å. The V(3)-O(8) bond length is 2.09 Å. There is one shorter (1.94 Å) and one longer (2.04 Å) V(3)-O(12) bond length. In the fourth V site, V(4) is bonded to one O(1), one O(10), one O(13), one O(2), and two equivalent O(3) atoms to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. The V(4)-O(1) bond length is 2.01 Å. The V(4)-O(10) bond length is 1.93 Å. The V(4)-O(13) bond length is 1.89 Å. The V(4)-O(2) bond length is 1.96 Å. There is one shorter (2.00 Å) and one longer (2.04 Å) V(4)-O(3) bond length. In the fifth V site, V(5) is bonded to one O(11), one O(15), one O(5), one O(6), and two equivalent O(9) atoms to form a mixture of distorted corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. The V(5)-O(11) bond length is 1.74 Å. The V(5)-O(15) bond length is 2.01 Å. The V(5)-O(5) bond length is 2.00 Å. The V(5)-O(6) bond length is 2.01 Å. There is one shorter (2.03 Å) and one longer (2.15 Å) V(5)-O(9) bond length. In the sixth V site, V(6) is bonded to one O(10), one O(11), one O(13), one O(14), one O(2), and one O(8) atom to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-53°. The V(6)-O(10) bond length is 2.00 Å. The V(6)-O(11) bond length is 2.11 Å. The V(6)-O(13) bond length is 1.98 Å. The V(6)-O(14) bond length is 1.99 Å. The V(6)-O(2) bond length is 1.97 Å. The V(6)-O(8) bond length is 2.07 Å. In the seventh V site, V(7) is bonded to one O(1), one O(12), one O(14), one O(2), one O(4), and one O(7) atom to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. The V(7)-O(1) bond length is 1.98 Å. The V(7)-O(12) bond length is 1.92 Å. The V(7)-O(14) bond length is 1.99 Å. The V(7)-O(2) bond length is 1.93 Å. The V(7)-O(4) bond length is 1.98 Å. The V(7)-O(7) bond length is 1.98 Å. In the eighth V site, V(8) is bonded to one O(11), one O(13), one O(4), one O(5), one O(6), and one O(7) atom to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 43-62°. The V(8)-O(11) bond length is 2.10 Å. The V(8)-O(13) bond length is 1.98 Å. The V(8)-O(4) bond length is 1.98 Å. The V(8)-O(5) bond length is 2.15 Å. The V(8)-O(6) bond length is 2.10 Å. The V(8)-O(7) bond length is 1.94 Å. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one V(3), one V(4), and one V(7) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one V(4), one V(6), and one V(7) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one V(3) and two equivalent V(4) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one V(2), one V(7), and one V(8) atom. In the fifth O site, O(5) is bonded to one V(5), one V(8), and two equivalent V(2) atoms to form a mixture of distorted corner and edge-sharing OV4 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one V(1), one V(2), one V(5), and one V(8) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one V(1), one V(7), and one V(8) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one V(1), one V(3), and one V(6) atom. In the ninth O site, O(9) is bonded to one V(1), one V(2), and two equivalent V(5) atoms to form a mixture of distorted corner and edge-sharing OV4 trigonal pyramids. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one V(3), one V(4), and one V(6) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one V(5), one V(6), and one V(8) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one V(7) and two equivalent V(3) atoms. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one V(4), one V(6), and one V(8) atom. In the fourteenth O site, O(14) is bonded in a trigonal planar geometry to one V(1), one V(6), and one V(7) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one V(1), one V(2), and one V(5) atom.