Rb4Mg(WO4)2 crystallizes in the monoclinic Cm space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one Mg(1), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to one Mg(1), one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms. In the fourth Rb site, Rb(4) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms. Mg(1) is bonded in an L-shaped geometry to one Rb(2), one Rb(3), one O(4), and one O(5) atom. There are two inequivalent W sites. In the first W site, W(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(1) atoms. In the second W site, W(2) is bonded in a tetrahedral geometry to one O(3), one O(6), and two equivalent O(2) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), and one W(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), and one W(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(3), two equivalent Rb(2), and one W(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Rb(4), two equivalent Rb(1), one Mg(1), and one W(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent Rb(4), one Mg(1), and one W(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Rb(2), two equivalent Rb(3), and one W(2) atom.
Rb4Mg(WO4)2 crystallizes in the monoclinic Cm space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. The Rb(1)-O(5) bond length is 3.06 Å. Both Rb(1)-O(1) bond lengths are 2.93 Å. Both Rb(1)-O(2) bond lengths are 3.16 Å. Both Rb(1)-O(4) bond lengths are 3.46 Å. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one Mg(1), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Rb(2)-Mg(1) bond length is 3.67 Å. The Rb(2)-O(6) bond length is 2.87 Å. Both Rb(2)-O(1) bond lengths are 3.17 Å. Both Rb(2)-O(2) bond lengths are 2.96 Å. Both Rb(2)-O(3) bond lengths are 3.39 Å. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to one Mg(1), one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms. The Rb(3)-Mg(1) bond length is 3.73 Å. The Rb(3)-O(3) bond length is 2.96 Å. Both Rb(3)-O(1) bond lengths are 2.82 Å. Both Rb(3)-O(2) bond lengths are 3.09 Å. Both Rb(3)-O(6) bond lengths are 3.43 Å. In the fourth Rb site, Rb(4) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms. The Rb(4)-O(4) bond length is 3.12 Å. Both Rb(4)-O(1) bond lengths are 3.08 Å. Both Rb(4)-O(2) bond lengths are 3.02 Å. Both Rb(4)-O(5) bond lengths are 3.49 Å. Mg(1) is bonded in an L-shaped geometry to one Rb(2), one Rb(3), one O(4), and one O(5) atom. The Mg(1)-O(4) bond length is 1.97 Å. The Mg(1)-O(5) bond length is 1.97 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(1) atoms. The W(1)-O(4) bond length is 1.96 Å. The W(1)-O(5) bond length is 1.97 Å. Both W(1)-O(1) bond lengths are 1.83 Å. In the second W site, W(2) is bonded in a tetrahedral geometry to one O(3), one O(6), and two equivalent O(2) atoms. The W(2)-O(3) bond length is 1.82 Å. The W(2)-O(6) bond length is 1.82 Å. Both W(2)-O(2) bond lengths are 1.83 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), and one W(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), and one W(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(3), two equivalent Rb(2), and one W(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Rb(4), two equivalent Rb(1), one Mg(1), and one W(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent Rb(4), one Mg(1), and one W(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Rb(2), two equivalent Rb(3), and one W(2) atom.