RbLi2B3Sb2O9 crystallizes in the monoclinic P2/c space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. Li(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra and corners with three equivalent Sb(1)O4 trigonal pyramids. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(5) and two equivalent O(4) atoms. Sb(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SbO4 trigonal pyramids that share corners with three equivalent Li(1)O4 tetrahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one B(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Rb(1), one Li(1), one B(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(1), one Li(1), one B(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one B(2), and one Sb(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Li(1), and one B(2) atom.
RbLi2B3Sb2O9 crystallizes in the monoclinic P2/c space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. Both Rb(1)-O(1) bond lengths are 3.49 Å. Both Rb(1)-O(2) bond lengths are 3.00 Å. Both Rb(1)-O(3) bond lengths are 2.91 Å. Both Rb(1)-O(5) bond lengths are 3.31 Å. Li(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra and corners with three equivalent Sb(1)O4 trigonal pyramids. The Li(1)-O(2) bond length is 2.03 Å. The Li(1)-O(3) bond length is 1.98 Å. The Li(1)-O(4) bond length is 2.14 Å. The Li(1)-O(5) bond length is 2.00 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The B(1)-O(1) bond length is 1.42 Å. The B(1)-O(2) bond length is 1.37 Å. The B(1)-O(3) bond length is 1.39 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(5) and two equivalent O(4) atoms. The B(2)-O(5) bond length is 1.34 Å. Both B(2)-O(4) bond lengths are 1.43 Å. Sb(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SbO4 trigonal pyramids that share corners with three equivalent Li(1)O4 tetrahedra. The Sb(1)-O(1) bond length is 2.03 Å. The Sb(1)-O(2) bond length is 2.30 Å. The Sb(1)-O(3) bond length is 2.20 Å. The Sb(1)-O(4) bond length is 2.05 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one B(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Rb(1), one Li(1), one B(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(1), one Li(1), one B(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one B(2), and one Sb(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Li(1), and one B(2) atom.