NaFe(SO7)2 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra. S(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 150 degrees geometry to one Na(1) and one S(1) atom. In the second O site, O(6) is bonded in a single-bond geometry to one S(1) atom. In the third O site, O(7) is bonded in a bent 120 degrees geometry to one Na(1) and one O(3) atom. In the fourth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Fe(1) and one S(1) atom. In the fifth O site, O(2) is bonded in a single-bond geometry to one Fe(1) atom. In the sixth O site, O(3) is bonded in a bent 120 degrees geometry to one Fe(1) and one O(7) atom. In the seventh O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Na(1) and one S(1) atom.
NaFe(SO7)2 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. Both Na(1)-O(4) bond lengths are 2.35 Å. Both Na(1)-O(5) bond lengths are 2.30 Å. Both Na(1)-O(7) bond lengths are 2.89 Å. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra. Both Fe(1)-O(1) bond lengths are 1.90 Å. Both Fe(1)-O(2) bond lengths are 1.78 Å. Both Fe(1)-O(3) bond lengths are 2.57 Å. S(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 46°. The S(1)-O(1) bond length is 1.57 Å. The S(1)-O(4) bond length is 1.48 Å. The S(1)-O(5) bond length is 1.45 Å. The S(1)-O(6) bond length is 1.48 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 150 degrees geometry to one Na(1) and one S(1) atom. In the second O site, O(6) is bonded in a single-bond geometry to one S(1) atom. In the third O site, O(7) is bonded in a bent 120 degrees geometry to one Na(1) and one O(3) atom. The O(7)-O(3) bond length is 1.23 Å. In the fourth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Fe(1) and one S(1) atom. In the fifth O site, O(2) is bonded in a single-bond geometry to one Fe(1) atom. In the sixth O site, O(3) is bonded in a bent 120 degrees geometry to one Fe(1) and one O(7) atom. In the seventh O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Na(1) and one S(1) atom.