Rb6Ge2O7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), and two equivalent O(4) atoms. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing GeO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Rb(3), and one Ge(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Rb(1), two equivalent Rb(2), and two equivalent Ge(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Rb(3), and one Ge(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(3), two equivalent Rb(2), and one Ge(1) atom.
Rb6Ge2O7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms. The Rb(1)-O(2) bond length is 3.02 Å. The Rb(1)-O(4) bond length is 2.87 Å. There is one shorter (2.89 Å) and one longer (3.06 Å) Rb(1)-O(1) bond length. There is one shorter (2.94 Å) and one longer (2.97 Å) Rb(1)-O(3) bond length. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), and two equivalent O(4) atoms. The Rb(2)-O(1) bond length is 2.89 Å. The Rb(2)-O(2) bond length is 3.08 Å. The Rb(2)-O(3) bond length is 3.04 Å. There is one shorter (2.90 Å) and one longer (2.98 Å) Rb(2)-O(4) bond length. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. The Rb(3)-O(4) bond length is 3.09 Å. There is one shorter (2.76 Å) and one longer (2.81 Å) Rb(3)-O(1) bond length. There is one shorter (2.79 Å) and one longer (2.81 Å) Rb(3)-O(3) bond length. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing GeO4 tetrahedra. The Ge(1)-O(1) bond length is 1.76 Å. The Ge(1)-O(2) bond length is 1.82 Å. The Ge(1)-O(3) bond length is 1.75 Å. The Ge(1)-O(4) bond length is 1.76 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Rb(3), and one Ge(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Rb(1), two equivalent Rb(2), and two equivalent Ge(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Rb(3), and one Ge(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(3), two equivalent Rb(2), and one Ge(1) atom.