Li6B4O9 crystallizes in the triclinic P-1 space group. There are six inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), and two equivalent O(5) atoms to form a mixture of distorted edge and corner-sharing LiO4 tetrahedra. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(5), and one O(8) atom. In the third Li site, Li(3) is bonded in a distorted see-saw-like geometry to one O(1), one O(7), and two equivalent O(2) atoms. In the fourth Li site, Li(4) is bonded in a 3-coordinate geometry to one O(5), one O(6), and one O(8) atom. In the fifth Li site, Li(5) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(8), and two equivalent O(7) atoms. In the sixth Li site, Li(6) is bonded to one O(3), one O(7), one O(8), and one O(9) atom to form distorted corner-sharing LiO4 tetrahedra. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(6), and one O(7) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(3), one O(4), and one O(8) atom. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(2), one O(6), and one O(9) atom. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(4), one O(5), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Li(5), and one B(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(1), two equivalent Li(3), and one B(3) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Li(6), and one B(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(5), one B(2), and one B(4) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Li(2), one Li(4), two equivalent Li(1), and one B(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(4), one B(1), and one B(3) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Li(3), one Li(6), two equivalent Li(5), and one B(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal bipyramidal geometry to one Li(2), one Li(4), one Li(5), one Li(6), and one B(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(6), one B(3), and one B(4) atom.
Li6B4O9 crystallizes in the triclinic P-1 space group. There are six inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), and two equivalent O(5) atoms to form a mixture of distorted edge and corner-sharing LiO4 tetrahedra. The Li(1)-O(2) bond length is 1.98 Å. The Li(1)-O(3) bond length is 1.95 Å. There is one shorter (1.99 Å) and one longer (2.01 Å) Li(1)-O(5) bond length. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(5), and one O(8) atom. The Li(2)-O(1) bond length is 1.86 Å. The Li(2)-O(3) bond length is 2.03 Å. The Li(2)-O(5) bond length is 2.37 Å. The Li(2)-O(8) bond length is 1.97 Å. In the third Li site, Li(3) is bonded in a distorted see-saw-like geometry to one O(1), one O(7), and two equivalent O(2) atoms. The Li(3)-O(1) bond length is 2.00 Å. The Li(3)-O(7) bond length is 2.12 Å. There is one shorter (1.99 Å) and one longer (2.04 Å) Li(3)-O(2) bond length. In the fourth Li site, Li(4) is bonded in a 3-coordinate geometry to one O(5), one O(6), and one O(8) atom. The Li(4)-O(5) bond length is 1.97 Å. The Li(4)-O(6) bond length is 1.97 Å. The Li(4)-O(8) bond length is 1.91 Å. In the fifth Li site, Li(5) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(8), and two equivalent O(7) atoms. The Li(5)-O(1) bond length is 2.34 Å. The Li(5)-O(4) bond length is 2.08 Å. The Li(5)-O(8) bond length is 2.02 Å. There is one shorter (2.00 Å) and one longer (2.08 Å) Li(5)-O(7) bond length. In the sixth Li site, Li(6) is bonded to one O(3), one O(7), one O(8), and one O(9) atom to form distorted corner-sharing LiO4 tetrahedra. The Li(6)-O(3) bond length is 2.00 Å. The Li(6)-O(7) bond length is 1.95 Å. The Li(6)-O(8) bond length is 2.13 Å. The Li(6)-O(9) bond length is 2.14 Å. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(6), and one O(7) atom. The B(1)-O(1) bond length is 1.35 Å. The B(1)-O(6) bond length is 1.47 Å. The B(1)-O(7) bond length is 1.38 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(3), one O(4), and one O(8) atom. The B(2)-O(3) bond length is 1.36 Å. The B(2)-O(4) bond length is 1.44 Å. The B(2)-O(8) bond length is 1.37 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(2), one O(6), and one O(9) atom. The B(3)-O(2) bond length is 1.33 Å. The B(3)-O(6) bond length is 1.42 Å. The B(3)-O(9) bond length is 1.42 Å. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(4), one O(5), and one O(9) atom. The B(4)-O(4) bond length is 1.41 Å. The B(4)-O(5) bond length is 1.35 Å. The B(4)-O(9) bond length is 1.41 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Li(5), and one B(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(1), two equivalent Li(3), and one B(3) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Li(6), and one B(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(5), one B(2), and one B(4) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Li(2), one Li(4), two equivalent Li(1), and one B(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(4), one B(1), and one B(3) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Li(3), one Li(6), two equivalent Li(5), and one B(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal bipyramidal geometry to one Li(2), one Li(4), one Li(5), one Li(6), and one B(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(6), one B(3), and one B(4) atom.