Na5MgSbO5 crystallizes in the triclinic P1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 3-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. In the second Na site, Na(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted NaO4 tetrahedra that share corners with three equivalent Na(4)O4 tetrahedra and corners with four equivalent Sb(1)O5 trigonal bipyramids. In the third Na site, Na(3) is bonded in a 3-coordinate geometry to one O(1), one O(2), and one O(3) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form distorted NaO4 tetrahedra that share corners with three equivalent Na(2)O4 tetrahedra, corners with two equivalent Sb(1)O5 trigonal bipyramids, and  an edgeedge with one Sb(1)O5 trigonal bipyramid. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(4) atom. Mg(1) is bonded in a 3-coordinate geometry to one O(1), one O(3), and one O(5) atom. Sb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted SbO5 trigonal bipyramids that share corners with two equivalent Na(4)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, and  an edgeedge with one Na(4)O4 tetrahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), one Mg(1), and one Sb(1) atom to form ONa4MgSb pentagonal pyramids that share corners with two equivalent O(3)Na4MgSb octahedra, corners with four equivalent O(4)Na4Sb trigonal bipyramids, edges with two equivalent O(2)Na4Sb trigonal bipyramids, and  a faceface with one O(3)Na4MgSb octahedra. The corner-sharing octahedral tilt angles range from 61-64°. In the second O site, O(2) is bonded to one Na(2), one Na(3), one Na(4), one Na(5), and one Sb(1) atom to form ONa4Sb trigonal bipyramids that share corners with four equivalent O(3)Na4MgSb octahedra, corners with two equivalent O(4)Na4Sb trigonal bipyramids, edges with two equivalent O(1)Na4MgSb pentagonal pyramids, and  an edgeedge with one O(4)Na4Sb trigonal bipyramid. The corner-sharing octahedral tilt angles range from 19-76°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(5), one Mg(1), and one Sb(1) atom to form distorted ONa4MgSb octahedra that share corners with two equivalent O(1)Na4MgSb pentagonal pyramids, corners with four equivalent O(2)Na4Sb trigonal bipyramids, edges with two equivalent O(4)Na4Sb trigonal bipyramids, and  a faceface with one O(1)Na4MgSb pentagonal pyramid. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), and one Sb(1) atom to form ONa4Sb trigonal bipyramids that share corners with four equivalent O(1)Na4MgSb pentagonal pyramids, corners with two equivalent O(2)Na4Sb trigonal bipyramids, edges with two equivalent O(3)Na4MgSb octahedra, and  an edgeedge with one O(2)Na4Sb trigonal bipyramid. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one Sb(1) atom.
Na5MgSbO5 crystallizes in the triclinic P1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 3-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. The Na(1)-O(1) bond length is 2.46 Å. The Na(1)-O(3) bond length is 2.36 Å. The Na(1)-O(4) bond length is 2.35 Å. The Na(1)-O(5) bond length is 2.87 Å. In the second Na site, Na(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form distorted NaO4 tetrahedra that share corners with three equivalent Na(4)O4 tetrahedra and corners with four equivalent Sb(1)O5 trigonal bipyramids. The Na(2)-O(2) bond length is 2.38 Å. The Na(2)-O(3) bond length is 2.65 Å. The Na(2)-O(4) bond length is 2.42 Å. The Na(2)-O(5) bond length is 2.59 Å. In the third Na site, Na(3) is bonded in a 3-coordinate geometry to one O(1), one O(2), and one O(3) atom. The Na(3)-O(1) bond length is 2.30 Å. The Na(3)-O(2) bond length is 2.49 Å. The Na(3)-O(3) bond length is 2.43 Å. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form distorted NaO4 tetrahedra that share corners with three equivalent Na(2)O4 tetrahedra, corners with two equivalent Sb(1)O5 trigonal bipyramids, and  an edgeedge with one Sb(1)O5 trigonal bipyramid. The Na(4)-O(1) bond length is 2.46 Å. The Na(4)-O(2) bond length is 2.43 Å. The Na(4)-O(4) bond length is 2.38 Å. The Na(4)-O(5) bond length is 2.45 Å. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Na(5)-O(1) bond length is 2.37 Å. The Na(5)-O(2) bond length is 2.44 Å. The Na(5)-O(3) bond length is 2.51 Å. The Na(5)-O(4) bond length is 2.33 Å. Mg(1) is bonded in a 3-coordinate geometry to one O(1), one O(3), and one O(5) atom. The Mg(1)-O(1) bond length is 2.29 Å. The Mg(1)-O(3) bond length is 2.06 Å. The Mg(1)-O(5) bond length is 2.11 Å. Sb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted SbO5 trigonal bipyramids that share corners with two equivalent Na(4)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, and  an edgeedge with one Na(4)O4 tetrahedra. The Sb(1)-O(1) bond length is 2.05 Å. The Sb(1)-O(2) bond length is 1.98 Å. The Sb(1)-O(3) bond length is 2.13 Å. The Sb(1)-O(4) bond length is 1.98 Å. The Sb(1)-O(5) bond length is 1.98 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), one Mg(1), and one Sb(1) atom to form ONa4MgSb pentagonal pyramids that share corners with two equivalent O(3)Na4MgSb octahedra, corners with four equivalent O(4)Na4Sb trigonal bipyramids, edges with two equivalent O(2)Na4Sb trigonal bipyramids, and  a faceface with one O(3)Na4MgSb octahedra. The corner-sharing octahedral tilt angles range from 61-64°. In the second O site, O(2) is bonded to one Na(2), one Na(3), one Na(4), one Na(5), and one Sb(1) atom to form ONa4Sb trigonal bipyramids that share corners with four equivalent O(3)Na4MgSb octahedra, corners with two equivalent O(4)Na4Sb trigonal bipyramids, edges with two equivalent O(1)Na4MgSb pentagonal pyramids, and  an edgeedge with one O(4)Na4Sb trigonal bipyramid. The corner-sharing octahedral tilt angles range from 19-76°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(5), one Mg(1), and one Sb(1) atom to form distorted ONa4MgSb octahedra that share corners with two equivalent O(1)Na4MgSb pentagonal pyramids, corners with four equivalent O(2)Na4Sb trigonal bipyramids, edges with two equivalent O(4)Na4Sb trigonal bipyramids, and  a faceface with one O(1)Na4MgSb pentagonal pyramid. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(4), one Na(5), and one Sb(1) atom to form ONa4Sb trigonal bipyramids that share corners with four equivalent O(1)Na4MgSb pentagonal pyramids, corners with two equivalent O(2)Na4Sb trigonal bipyramids, edges with two equivalent O(3)Na4MgSb octahedra, and  an edgeedge with one O(2)Na4Sb trigonal bipyramid. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one Sb(1) atom.