RbKGeO3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), two equivalent O(4), and three equivalent O(5) atoms. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), and two equivalent O(1) atoms. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. In the second K site, K(2) is bonded to one O(1), one O(2), and three equivalent O(3) atoms to form distorted KO5 square pyramids that share corners with two equivalent K(2)O5 square pyramids, corners with two equivalent Ge(1)O4 tetrahedra, corners with three equivalent Ge(2)O4 tetrahedra, and edges with two equivalent K(2)O5 square pyramids. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form GeO4 tetrahedra that share corners with two equivalent K(2)O5 square pyramids and corners with two equivalent Ge(2)O4 tetrahedra. In the second Ge site, Ge(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form GeO4 tetrahedra that share corners with three equivalent K(2)O5 square pyramids and corners with two equivalent Ge(1)O4 tetrahedra. There are five inequivalent O sites. In the first O site, O(3) is bonded in a 6-coordinate geometry to one Rb(2), one K(1), three equivalent K(2), and one Ge(2) atom. In the second O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Rb(1), one K(1), one Ge(1), and one Ge(2) atom. In the third O site, O(5) is bonded in a distorted single-bond geometry to one Rb(2), three equivalent Rb(1), one K(1), and one Ge(2) atom. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), one K(1), one K(2), and one Ge(1) atom. In the fifth O site, O(2) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(2), one K(2), two equivalent K(1), and one Ge(1) atom.
RbKGeO3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), two equivalent O(4), and three equivalent O(5) atoms. The Rb(1)-O(1) bond length is 3.07 Å. The Rb(1)-O(2) bond length is 3.27 Å. Both Rb(1)-O(4) bond lengths are 3.25 Å. There are two shorter (2.93 Å) and one longer (3.05 Å) Rb(1)-O(5) bond length. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), and two equivalent O(1) atoms. The Rb(2)-O(2) bond length is 2.89 Å. The Rb(2)-O(3) bond length is 3.07 Å. The Rb(2)-O(5) bond length is 2.88 Å. Both Rb(2)-O(1) bond lengths are 2.96 Å. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. The K(1)-O(1) bond length is 2.86 Å. The K(1)-O(3) bond length is 2.82 Å. The K(1)-O(5) bond length is 3.18 Å. Both K(1)-O(2) bond lengths are 2.89 Å. Both K(1)-O(4) bond lengths are 2.98 Å. In the second K site, K(2) is bonded to one O(1), one O(2), and three equivalent O(3) atoms to form distorted KO5 square pyramids that share corners with two equivalent K(2)O5 square pyramids, corners with two equivalent Ge(1)O4 tetrahedra, corners with three equivalent Ge(2)O4 tetrahedra, and edges with two equivalent K(2)O5 square pyramids. The K(2)-O(1) bond length is 2.80 Å. The K(2)-O(2) bond length is 2.63 Å. There is one shorter (2.65 Å) and two longer (2.89 Å) K(2)-O(3) bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form GeO4 tetrahedra that share corners with two equivalent K(2)O5 square pyramids and corners with two equivalent Ge(2)O4 tetrahedra. The Ge(1)-O(1) bond length is 1.74 Å. The Ge(1)-O(2) bond length is 1.74 Å. Both Ge(1)-O(4) bond lengths are 1.84 Å. In the second Ge site, Ge(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form GeO4 tetrahedra that share corners with three equivalent K(2)O5 square pyramids and corners with two equivalent Ge(1)O4 tetrahedra. The Ge(2)-O(3) bond length is 1.75 Å. The Ge(2)-O(5) bond length is 1.74 Å. Both Ge(2)-O(4) bond lengths are 1.84 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a 6-coordinate geometry to one Rb(2), one K(1), three equivalent K(2), and one Ge(2) atom. In the second O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Rb(1), one K(1), one Ge(1), and one Ge(2) atom. In the third O site, O(5) is bonded in a distorted single-bond geometry to one Rb(2), three equivalent Rb(1), one K(1), and one Ge(2) atom. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), one K(1), one K(2), and one Ge(1) atom. In the fifth O site, O(2) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(2), one K(2), two equivalent K(1), and one Ge(1) atom.