Na2Mg2Fe2Se3(SO8)3 crystallizes in the trigonal R3 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a hexagonal planar geometry to three equivalent O(5) and three equivalent O(6) atoms. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to three equivalent O(7) and three equivalent O(8) atoms. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent O(3) and three equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. In the second Mg site, Mg(2) is bonded to three equivalent O(4) and three equivalent O(8) atoms to form MgO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(1) and three equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(2) and three equivalent O(6) atoms to form FeO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. Se(1) is bonded to one O(2), one O(3), one O(5), and one O(8) atom to form SeO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, and  a cornercorner with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-44°. S(1) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form SO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, and  a cornercorner with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-39°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(2) and one Se(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(2) and one S(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one Se(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Fe(2), and one S(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Mg(1), and one S(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Na(2), one Mg(2), and one Se(1) atom.
Na2Mg2Fe2Se3(SO8)3 crystallizes in the trigonal R3 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a hexagonal planar geometry to three equivalent O(5) and three equivalent O(6) atoms. All Na(1)-O(5) bond lengths are 2.52 Å. All Na(1)-O(6) bond lengths are 2.54 Å. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to three equivalent O(7) and three equivalent O(8) atoms. All Na(2)-O(7) bond lengths are 2.57 Å. All Na(2)-O(8) bond lengths are 2.51 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent O(3) and three equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. All Mg(1)-O(3) bond lengths are 2.07 Å. All Mg(1)-O(7) bond lengths are 2.13 Å. In the second Mg site, Mg(2) is bonded to three equivalent O(4) and three equivalent O(8) atoms to form MgO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. All Mg(2)-O(4) bond lengths are 2.06 Å. All Mg(2)-O(8) bond lengths are 2.11 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(1) and three equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. All Fe(1)-O(1) bond lengths are 2.00 Å. All Fe(1)-O(5) bond lengths are 2.05 Å. In the second Fe site, Fe(2) is bonded to three equivalent O(2) and three equivalent O(6) atoms to form FeO6 octahedra that share corners with three equivalent Se(1)O4 tetrahedra and corners with three equivalent S(1)O4 tetrahedra. All Fe(2)-O(2) bond lengths are 1.97 Å. All Fe(2)-O(6) bond lengths are 2.06 Å. Se(1) is bonded to one O(2), one O(3), one O(5), and one O(8) atom to form SeO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, and  a cornercorner with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-44°. The Se(1)-O(2) bond length is 1.67 Å. The Se(1)-O(3) bond length is 1.65 Å. The Se(1)-O(5) bond length is 1.68 Å. The Se(1)-O(8) bond length is 1.66 Å. S(1) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form SO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, and  a cornercorner with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-39°. The S(1)-O(1) bond length is 1.50 Å. The S(1)-O(4) bond length is 1.47 Å. The S(1)-O(6) bond length is 1.51 Å. The S(1)-O(7) bond length is 1.48 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(2) and one Se(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(2) and one S(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one Se(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Fe(2), and one S(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Mg(1), and one S(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Na(2), one Mg(2), and one Se(1) atom.