Na4Mg(Mo2O5)2 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(9) atom. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(6), and one O(8) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(2), one O(4), and one O(5) atom. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(8), and one O(9) atom. Mg(1) is bonded to one O(10), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO5 square pyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mo(4)O5 trigonal bipyramid, and  an edgeedge with one Mo(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 21-42°. There are four inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MoO6 octahedra that share corners with four equivalent Mo(2)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, and  an edgeedge with one Mo(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 2-45°. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form MoO6 octahedra that share corners with four equivalent Mo(1)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, and corners with two equivalent Mo(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 2-45°. In the third Mo site, Mo(3) is bonded in a distorted rectangular see-saw-like geometry to one O(10), one O(5), one O(8), and one O(9) atom. In the fourth Mo site, Mo(4) is bonded to one O(10), one O(3), one O(6), one O(7), and one O(9) atom to form distorted MoO5 trigonal bipyramids that share corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mg(1)O5 square pyramid,  an edgeedge with one Mo(1)O6 octahedra, and  an edgeedge with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 47-52°. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Mo(1), and one Mo(2) atom to form distorted ONa4Mo2 octahedra that share corners with two equivalent O(9)Na2Mo2 tetrahedra,  a cornercorner with one O(6)Na2MgMo2 trigonal bipyramid, and  an edgeedge with one O(6)Na2MgMo2 trigonal bipyramid. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mo(1), and one Mo(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(2), one Na(4), one Mo(1), one Mo(2), and one Mo(4) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mo(1), and one Mo(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Mg(1), one Mo(1), and one Mo(3) atom. In the sixth O site, O(6) is bonded to one Na(2), one Na(4), one Mg(1), one Mo(1), and one Mo(4) atom to form distorted ONa2MgMo2 trigonal bipyramids that share  a cornercorner with one O(1)Na4Mo2 octahedra, corners with two equivalent O(9)Na2Mo2 tetrahedra, and  an edgeedge with one O(1)Na4Mo2 octahedra. The corner-sharing octahedral tilt angles are 53°. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Mg(1), one Mo(2), and one Mo(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(2), one Na(4), one Mg(1), one Mo(2), and one Mo(3) atom. In the ninth O site, O(9) is bonded to one Na(1), one Na(4), one Mo(3), and one Mo(4) atom to form ONa2Mo2 tetrahedra that share corners with two equivalent O(1)Na4Mo2 octahedra and corners with two equivalent O(6)Na2MgMo2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 17-83°. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), one Mg(1), one Mo(3), and one Mo(4) atom.
Na4Mg(Mo2O5)2 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(9) atom. The Na(1)-O(1) bond length is 2.42 Å. The Na(1)-O(2) bond length is 2.39 Å. The Na(1)-O(4) bond length is 2.92 Å. The Na(1)-O(5) bond length is 2.82 Å. The Na(1)-O(7) bond length is 2.45 Å. The Na(1)-O(9) bond length is 2.24 Å. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(6), and one O(8) atom. The Na(2)-O(1) bond length is 2.39 Å. The Na(2)-O(10) bond length is 2.54 Å. The Na(2)-O(2) bond length is 2.45 Å. The Na(2)-O(3) bond length is 2.37 Å. The Na(2)-O(4) bond length is 2.38 Å. The Na(2)-O(6) bond length is 2.45 Å. The Na(2)-O(8) bond length is 2.50 Å. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(2), one O(4), and one O(5) atom. The Na(3)-O(1) bond length is 2.28 Å. The Na(3)-O(10) bond length is 2.27 Å. The Na(3)-O(2) bond length is 2.32 Å. The Na(3)-O(4) bond length is 2.43 Å. The Na(3)-O(5) bond length is 2.65 Å. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(8), and one O(9) atom. The Na(4)-O(1) bond length is 2.68 Å. The Na(4)-O(2) bond length is 2.81 Å. The Na(4)-O(3) bond length is 2.46 Å. The Na(4)-O(4) bond length is 2.31 Å. The Na(4)-O(6) bond length is 2.48 Å. The Na(4)-O(8) bond length is 2.75 Å. The Na(4)-O(9) bond length is 2.22 Å. Mg(1) is bonded to one O(10), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO5 square pyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mo(4)O5 trigonal bipyramid, and  an edgeedge with one Mo(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 21-42°. The Mg(1)-O(10) bond length is 2.02 Å. The Mg(1)-O(5) bond length is 2.01 Å. The Mg(1)-O(6) bond length is 1.97 Å. The Mg(1)-O(7) bond length is 2.04 Å. The Mg(1)-O(8) bond length is 2.24 Å. There are four inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MoO6 octahedra that share corners with four equivalent Mo(2)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, and  an edgeedge with one Mo(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 2-45°. The Mo(1)-O(1) bond length is 2.09 Å. The Mo(1)-O(2) bond length is 2.06 Å. The Mo(1)-O(3) bond length is 2.14 Å. The Mo(1)-O(4) bond length is 2.06 Å. The Mo(1)-O(5) bond length is 2.18 Å. The Mo(1)-O(6) bond length is 2.12 Å. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form MoO6 octahedra that share corners with four equivalent Mo(1)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, and corners with two equivalent Mo(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 2-45°. The Mo(2)-O(1) bond length is 2.18 Å. The Mo(2)-O(2) bond length is 2.20 Å. The Mo(2)-O(3) bond length is 2.38 Å. The Mo(2)-O(4) bond length is 2.21 Å. The Mo(2)-O(7) bond length is 2.22 Å. The Mo(2)-O(8) bond length is 2.23 Å. In the third Mo site, Mo(3) is bonded in a distorted rectangular see-saw-like geometry to one O(10), one O(5), one O(8), and one O(9) atom. The Mo(3)-O(10) bond length is 1.98 Å. The Mo(3)-O(5) bond length is 2.01 Å. The Mo(3)-O(8) bond length is 1.94 Å. The Mo(3)-O(9) bond length is 1.95 Å. In the fourth Mo site, Mo(4) is bonded to one O(10), one O(3), one O(6), one O(7), and one O(9) atom to form distorted MoO5 trigonal bipyramids that share corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mg(1)O5 square pyramid,  an edgeedge with one Mo(1)O6 octahedra, and  an edgeedge with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 47-52°. The Mo(4)-O(10) bond length is 2.13 Å. The Mo(4)-O(3) bond length is 2.41 Å. The Mo(4)-O(6) bond length is 2.04 Å. The Mo(4)-O(7) bond length is 2.14 Å. The Mo(4)-O(9) bond length is 2.06 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Mo(1), and one Mo(2) atom to form distorted ONa4Mo2 octahedra that share corners with two equivalent O(9)Na2Mo2 tetrahedra,  a cornercorner with one O(6)Na2MgMo2 trigonal bipyramid, and  an edgeedge with one O(6)Na2MgMo2 trigonal bipyramid. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mo(1), and one Mo(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(2), one Na(4), one Mo(1), one Mo(2), and one Mo(4) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mo(1), and one Mo(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Mg(1), one Mo(1), and one Mo(3) atom. In the sixth O site, O(6) is bonded to one Na(2), one Na(4), one Mg(1), one Mo(1), and one Mo(4) atom to form distorted ONa2MgMo2 trigonal bipyramids that share  a cornercorner with one O(1)Na4Mo2 octahedra, corners with two equivalent O(9)Na2Mo2 tetrahedra, and  an edgeedge with one O(1)Na4Mo2 octahedra. The corner-sharing octahedral tilt angles are 53°. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Mg(1), one Mo(2), and one Mo(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(2), one Na(4), one Mg(1), one Mo(2), and one Mo(3) atom. In the ninth O site, O(9) is bonded to one Na(1), one Na(4), one Mo(3), and one Mo(4) atom to form ONa2Mo2 tetrahedra that share corners with two equivalent O(1)Na4Mo2 octahedra and corners with two equivalent O(6)Na2MgMo2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 17-83°. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), one Mg(1), one Mo(3), and one Mo(4) atom.