Rb6Al4(Sb2O7)3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. In the second Rb site, Rb(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(4), and four equivalent O(2) atoms. In the third Rb site, Rb(3) is bonded in a 9-coordinate geometry to two equivalent O(1), three equivalent O(6), and four equivalent O(3) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a tetrahedral geometry to one O(6), one O(7), and two equivalent O(1) atoms. In the second Al site, Al(2) is bonded to one O(4), one O(8), and two equivalent O(2) atoms to form corner-sharing AlO4 tetrahedra. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a distorted T-shaped geometry to one O(5) and two equivalent O(2) atoms. In the second Sb site, Sb(2) is bonded in a distorted T-shaped geometry to one O(4) and two equivalent O(1) atoms. In the third Sb site, Sb(3) is bonded in a distorted T-shaped geometry to one O(6) and two equivalent O(3) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Al(1), and one Sb(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent Rb(2), one Al(2), and one Sb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(1), two equivalent Rb(3), and one Sb(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Rb(1), two equivalent Rb(2), one Al(2), and one Sb(2) atom. In the fifth O site, O(5) is bonded to one Rb(2), two equivalent Rb(1), and one Sb(1) atom to form distorted corner-sharing ORb3Sb trigonal pyramids. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to three equivalent Rb(3), one Al(1), and one Sb(3) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one Al(1) atom. In the eighth O site, O(8) is bonded in a linear geometry to two equivalent Al(2) atoms.
Rb6Al4(Sb2O7)3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. The Rb(1)-O(4) bond length is 3.52 Å. Both Rb(1)-O(1) bond lengths are 3.37 Å. Both Rb(1)-O(2) bond lengths are 3.37 Å. Both Rb(1)-O(3) bond lengths are 2.91 Å. Both Rb(1)-O(5) bond lengths are 3.03 Å. In the second Rb site, Rb(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(4), and four equivalent O(2) atoms. The Rb(2)-O(5) bond length is 3.02 Å. Both Rb(2)-O(1) bond lengths are 3.12 Å. Both Rb(2)-O(4) bond lengths are 3.12 Å. There are two shorter (3.08 Å) and two longer (3.27 Å) Rb(2)-O(2) bond lengths. In the third Rb site, Rb(3) is bonded in a 9-coordinate geometry to two equivalent O(1), three equivalent O(6), and four equivalent O(3) atoms. Both Rb(3)-O(1) bond lengths are 3.32 Å. There are two shorter (3.14 Å) and one longer (3.51 Å) Rb(3)-O(6) bond length. There are two shorter (2.99 Å) and two longer (3.01 Å) Rb(3)-O(3) bond lengths. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a tetrahedral geometry to one O(6), one O(7), and two equivalent O(1) atoms. The Al(1)-O(6) bond length is 1.77 Å. The Al(1)-O(7) bond length is 1.79 Å. Both Al(1)-O(1) bond lengths are 1.78 Å. In the second Al site, Al(2) is bonded to one O(4), one O(8), and two equivalent O(2) atoms to form corner-sharing AlO4 tetrahedra. The Al(2)-O(4) bond length is 1.79 Å. The Al(2)-O(8) bond length is 1.73 Å. Both Al(2)-O(2) bond lengths are 1.79 Å. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a distorted T-shaped geometry to one O(5) and two equivalent O(2) atoms. The Sb(1)-O(5) bond length is 1.91 Å. Both Sb(1)-O(2) bond lengths are 1.97 Å. In the second Sb site, Sb(2) is bonded in a distorted T-shaped geometry to one O(4) and two equivalent O(1) atoms. The Sb(2)-O(4) bond length is 1.97 Å. Both Sb(2)-O(1) bond lengths are 1.98 Å. In the third Sb site, Sb(3) is bonded in a distorted T-shaped geometry to one O(6) and two equivalent O(3) atoms. The Sb(3)-O(6) bond length is 2.01 Å. Both Sb(3)-O(3) bond lengths are 1.96 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Al(1), and one Sb(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent Rb(2), one Al(2), and one Sb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(1), two equivalent Rb(3), and one Sb(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Rb(1), two equivalent Rb(2), one Al(2), and one Sb(2) atom. In the fifth O site, O(5) is bonded to one Rb(2), two equivalent Rb(1), and one Sb(1) atom to form distorted corner-sharing ORb3Sb trigonal pyramids. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to three equivalent Rb(3), one Al(1), and one Sb(3) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one Al(1) atom. In the eighth O site, O(8) is bonded in a linear geometry to two equivalent Al(2) atoms.