RbNaMg6O7 crystallizes in the tetragonal P4mm space group. Rb(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(4) atoms. Na(1) is bonded in a square co-planar geometry to four equivalent O(4) atoms. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1) and four equivalent O(5) atoms to form MgO5 square pyramids that share corners with four equivalent Mg(1)O5 square pyramids, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(4)O5 square pyramids. In the second Mg site, Mg(2) is bonded to one O(2), one O(3), and four equivalent O(5) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, edges with four equivalent Mg(1)O5 square pyramids, and edges with four equivalent Mg(4)O5 square pyramids. The corner-sharing octahedral tilt angles are 5°. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one O(4), one O(5), and two equivalent O(2) atoms. In the fourth Mg site, Mg(4) is bonded to one O(5), two equivalent O(1), and two equivalent O(3) atoms to form MgO5 square pyramids that share corners with four equivalent Mg(4)O5 square pyramids, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O5 square pyramids, and edges with four equivalent Mg(4)O5 square pyramids. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1) and four equivalent Mg(4) atoms to form OMg5 square pyramids that share corners with four equivalent O(1)Mg5 square pyramids, edges with four equivalent O(5)Mg6 octahedra, and edges with four equivalent O(3)RbMg5 octahedra. In the second O site, O(2) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form distorted OMg5 square pyramids that share  a cornercorner with one O(3)RbMg5 octahedra, corners with four equivalent O(2)Mg5 square pyramids, and edges with four equivalent O(5)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded to one Rb(1), one Mg(2), and four equivalent Mg(4) atoms to form distorted ORbMg5 octahedra that share corners with four equivalent O(3)RbMg5 octahedra,  a cornercorner with one O(2)Mg5 square pyramid, edges with four equivalent O(5)Mg6 octahedra, and edges with four equivalent O(1)Mg5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Rb(1), two equivalent Na(1), and one Mg(3) atom. In the fifth O site, O(5) is bonded to one Mg(3), one Mg(4), two equivalent Mg(1), and two equivalent Mg(2) atoms to form OMg6 octahedra that share corners with four equivalent O(5)Mg6 octahedra, edges with two equivalent O(3)RbMg5 octahedra, edges with four equivalent O(5)Mg6 octahedra, edges with two equivalent O(1)Mg5 square pyramids, and edges with two equivalent O(2)Mg5 square pyramids. The corner-sharing octahedral tilt angles range from 4-5°.
RbNaMg6O7 crystallizes in the tetragonal P4mm space group. Rb(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(4) atoms. The Rb(1)-O(3) bond length is 3.30 Å. All Rb(1)-O(4) bond lengths are 2.67 Å. Na(1) is bonded in a square co-planar geometry to four equivalent O(4) atoms. All Na(1)-O(4) bond lengths are 2.18 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1) and four equivalent O(5) atoms to form MgO5 square pyramids that share corners with four equivalent Mg(1)O5 square pyramids, edges with four equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(4)O5 square pyramids. The Mg(1)-O(1) bond length is 2.12 Å. All Mg(1)-O(5) bond lengths are 2.13 Å. In the second Mg site, Mg(2) is bonded to one O(2), one O(3), and four equivalent O(5) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, edges with four equivalent Mg(1)O5 square pyramids, and edges with four equivalent Mg(4)O5 square pyramids. The corner-sharing octahedral tilt angles are 5°. The Mg(2)-O(2) bond length is 2.00 Å. The Mg(2)-O(3) bond length is 2.32 Å. All Mg(2)-O(5) bond lengths are 2.13 Å. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one O(4), one O(5), and two equivalent O(2) atoms. The Mg(3)-O(4) bond length is 1.89 Å. The Mg(3)-O(5) bond length is 2.54 Å. Both Mg(3)-O(2) bond lengths are 2.17 Å. In the fourth Mg site, Mg(4) is bonded to one O(5), two equivalent O(1), and two equivalent O(3) atoms to form MgO5 square pyramids that share corners with four equivalent Mg(4)O5 square pyramids, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(1)O5 square pyramids, and edges with four equivalent Mg(4)O5 square pyramids. The Mg(4)-O(5) bond length is 2.09 Å. Both Mg(4)-O(1) bond lengths are 2.13 Å. Both Mg(4)-O(3) bond lengths are 2.13 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1) and four equivalent Mg(4) atoms to form OMg5 square pyramids that share corners with four equivalent O(1)Mg5 square pyramids, edges with four equivalent O(5)Mg6 octahedra, and edges with four equivalent O(3)RbMg5 octahedra. In the second O site, O(2) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form distorted OMg5 square pyramids that share  a cornercorner with one O(3)RbMg5 octahedra, corners with four equivalent O(2)Mg5 square pyramids, and edges with four equivalent O(5)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded to one Rb(1), one Mg(2), and four equivalent Mg(4) atoms to form distorted ORbMg5 octahedra that share corners with four equivalent O(3)RbMg5 octahedra,  a cornercorner with one O(2)Mg5 square pyramid, edges with four equivalent O(5)Mg6 octahedra, and edges with four equivalent O(1)Mg5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Rb(1), two equivalent Na(1), and one Mg(3) atom. In the fifth O site, O(5) is bonded to one Mg(3), one Mg(4), two equivalent Mg(1), and two equivalent Mg(2) atoms to form OMg6 octahedra that share corners with four equivalent O(5)Mg6 octahedra, edges with two equivalent O(3)RbMg5 octahedra, edges with four equivalent O(5)Mg6 octahedra, edges with two equivalent O(1)Mg5 square pyramids, and edges with two equivalent O(2)Mg5 square pyramids. The corner-sharing octahedral tilt angles range from 4-5°.