Rb3NaMg(MoO4)2 crystallizes in the trigonal P3m1 space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to one O(4) and six equivalent O(1) atoms to form RbO7 hexagonal pyramids that share corners with six equivalent Rb(1)O7 hexagonal pyramids,  a cornercorner with one Mo(2)O4 tetrahedra, and edges with three equivalent Mo(1)O4 tetrahedra. In the second Rb site, Rb(2) is bonded in a 10-coordinate geometry to one O(3), three equivalent O(1), and six equivalent O(2) atoms. In the third Rb site, Rb(3) is bonded in a 4-coordinate geometry to one Mg(1) and three equivalent O(2) atoms. Na(1) is bonded in a 3-coordinate geometry to three equivalent O(2) atoms. Mg(1) is bonded in a distorted trigonal planar geometry to one Rb(3) and three equivalent O(1) atoms. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(3) and three equivalent O(1) atoms to form distorted MoO4 tetrahedra that share edges with three equivalent Rb(1)O7 hexagonal pyramids. In the second Mo site, Mo(2) is bonded to one O(4) and three equivalent O(2) atoms to form MoO4 tetrahedra that share  a cornercorner with one Rb(1)O7 hexagonal pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Rb(2), two equivalent Rb(1), one Mg(1), and one Mo(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(3), two equivalent Rb(2), one Na(1), and one Mo(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(2) and one Mo(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Rb(1) and one Mo(2) atom.
Rb3NaMg(MoO4)2 crystallizes in the trigonal P3m1 space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to one O(4) and six equivalent O(1) atoms to form RbO7 hexagonal pyramids that share corners with six equivalent Rb(1)O7 hexagonal pyramids,  a cornercorner with one Mo(2)O4 tetrahedra, and edges with three equivalent Mo(1)O4 tetrahedra. The Rb(1)-O(4) bond length is 3.06 Å. All Rb(1)-O(1) bond lengths are 3.14 Å. In the second Rb site, Rb(2) is bonded in a 10-coordinate geometry to one O(3), three equivalent O(1), and six equivalent O(2) atoms. The Rb(2)-O(3) bond length is 3.30 Å. All Rb(2)-O(1) bond lengths are 3.34 Å. All Rb(2)-O(2) bond lengths are 3.22 Å. In the third Rb site, Rb(3) is bonded in a 4-coordinate geometry to one Mg(1) and three equivalent O(2) atoms. The Rb(3)-Mg(1) bond length is 3.02 Å. All Rb(3)-O(2) bond lengths are 2.83 Å. Na(1) is bonded in a 3-coordinate geometry to three equivalent O(2) atoms. All Na(1)-O(2) bond lengths are 2.26 Å. Mg(1) is bonded in a distorted trigonal planar geometry to one Rb(3) and three equivalent O(1) atoms. All Mg(1)-O(1) bond lengths are 1.88 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(3) and three equivalent O(1) atoms to form distorted MoO4 tetrahedra that share edges with three equivalent Rb(1)O7 hexagonal pyramids. The Mo(1)-O(3) bond length is 1.83 Å. All Mo(1)-O(1) bond lengths are 2.02 Å. In the second Mo site, Mo(2) is bonded to one O(4) and three equivalent O(2) atoms to form MoO4 tetrahedra that share  a cornercorner with one Rb(1)O7 hexagonal pyramid. The Mo(2)-O(4) bond length is 1.77 Å. All Mo(2)-O(2) bond lengths are 1.81 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Rb(2), two equivalent Rb(1), one Mg(1), and one Mo(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(3), two equivalent Rb(2), one Na(1), and one Mo(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(2) and one Mo(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Rb(1) and one Mo(2) atom.