Na8Mg(FeO4)2 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(6), one O(7), and one O(8) atom. In the second Na site, Na(2) is bonded to one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted NaO5 trigonal bipyramids that share corners with three equivalent Na(6)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Na(4)O4 trigonal pyramid,  an edgeedge with one Na(6)O5 square pyramid,  an edgeedge with one Mg(1)O4 tetrahedra,  an edgeedge with one Fe(1)O4 tetrahedra,  an edgeedge with one Fe(2)O4 tetrahedra, and edges with two equivalent Na(5)O5 trigonal bipyramids. In the third Na site, Na(3) is bonded in a distorted see-saw-like geometry to one O(1), one O(5), one O(6), and one O(7) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Na(6)O5 square pyramid, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid,  a cornercorner with one Na(5)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O4 tetrahedra. In the fifth Na site, Na(5) is bonded to one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(4)O4 trigonal pyramid, edges with two equivalent Na(6)O5 square pyramids,  an edgeedge with one Mg(1)O4 tetrahedra,  an edgeedge with one Fe(2)O4 tetrahedra, and edges with two equivalent Na(2)O5 trigonal bipyramids. In the sixth Na site, Na(6) is bonded to one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with three equivalent Na(2)O5 trigonal bipyramids,  a cornercorner with one Na(4)O4 trigonal pyramid,  an edgeedge with one Mg(1)O4 tetrahedra,  an edgeedge with one Fe(1)O4 tetrahedra,  an edgeedge with one Na(2)O5 trigonal bipyramid, and edges with two equivalent Na(5)O5 trigonal bipyramids. In the seventh Na site, Na(7) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(5), one O(6), and one O(7) atom. In the eighth Na site, Na(8) is bonded in a 3-coordinate geometry to one O(1), one O(2), one O(4), and one O(5) atom. Mg(1) is bonded to one O(1), one O(2), one O(4), and one O(8) atom to form MgO4 tetrahedra that share  a cornercorner with one Na(6)O5 square pyramid,  a cornercorner with one Fe(2)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid,  an edgeedge with one Na(6)O5 square pyramid,  an edgeedge with one Na(2)O5 trigonal bipyramid,  an edgeedge with one Na(5)O5 trigonal bipyramid, and  an edgeedge with one Na(4)O4 trigonal pyramid. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Na(6)O5 square pyramid, corners with three equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid, corners with two equivalent Na(5)O5 trigonal bipyramids, corners with two equivalent Na(4)O4 trigonal pyramids,  an edgeedge with one Na(6)O5 square pyramid, and  an edgeedge with one Na(2)O5 trigonal bipyramid. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with two equivalent Na(6)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Na(5)O5 trigonal bipyramid, corners with two equivalent Na(4)O4 trigonal pyramids,  an edgeedge with one Na(2)O5 trigonal bipyramid, and  an edgeedge with one Na(5)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), one Na(4), one Na(8), one Mg(1), and one Fe(2) atom to form distorted corner-sharing ONa3MgFe trigonal bipyramids. The corner-sharing octahedral tilt angles are 64°. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), one Na(4), one Na(6), one Na(8), one Mg(1), and one Fe(1) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), and one Fe(2) atom to form distorted corner-sharing ONa5Fe octahedra. In the fourth O site, O(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(8), one Mg(1), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Na(8), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(5), one Na(7), and one Fe(2) atom. In the seventh O site, O(7) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(5), one Na(6), one Na(7), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Mg(1), and one Fe(1) atom.
Na8Mg(FeO4)2 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(6), one O(7), and one O(8) atom. The Na(1)-O(3) bond length is 2.42 Å. The Na(1)-O(4) bond length is 2.89 Å. The Na(1)-O(6) bond length is 2.30 Å. The Na(1)-O(7) bond length is 2.60 Å. The Na(1)-O(8) bond length is 2.45 Å. In the second Na site, Na(2) is bonded to one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted NaO5 trigonal bipyramids that share corners with three equivalent Na(6)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Na(4)O4 trigonal pyramid,  an edgeedge with one Na(6)O5 square pyramid,  an edgeedge with one Mg(1)O4 tetrahedra,  an edgeedge with one Fe(1)O4 tetrahedra,  an edgeedge with one Fe(2)O4 tetrahedra, and edges with two equivalent Na(5)O5 trigonal bipyramids. The Na(2)-O(2) bond length is 2.52 Å. The Na(2)-O(3) bond length is 2.29 Å. The Na(2)-O(4) bond length is 2.51 Å. The Na(2)-O(7) bond length is 2.40 Å. The Na(2)-O(8) bond length is 2.58 Å. In the third Na site, Na(3) is bonded in a distorted see-saw-like geometry to one O(1), one O(5), one O(6), and one O(7) atom. The Na(3)-O(1) bond length is 2.27 Å. The Na(3)-O(5) bond length is 2.23 Å. The Na(3)-O(6) bond length is 2.30 Å. The Na(3)-O(7) bond length is 2.50 Å. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Na(6)O5 square pyramid, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid,  a cornercorner with one Na(5)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O4 tetrahedra. The Na(4)-O(1) bond length is 2.41 Å. The Na(4)-O(2) bond length is 2.46 Å. The Na(4)-O(5) bond length is 2.29 Å. The Na(4)-O(6) bond length is 2.40 Å. In the fifth Na site, Na(5) is bonded to one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(4)O4 trigonal pyramid, edges with two equivalent Na(6)O5 square pyramids,  an edgeedge with one Mg(1)O4 tetrahedra,  an edgeedge with one Fe(2)O4 tetrahedra, and edges with two equivalent Na(2)O5 trigonal bipyramids. The Na(5)-O(3) bond length is 2.54 Å. The Na(5)-O(4) bond length is 2.45 Å. The Na(5)-O(6) bond length is 2.39 Å. The Na(5)-O(7) bond length is 2.47 Å. The Na(5)-O(8) bond length is 2.35 Å. In the sixth Na site, Na(6) is bonded to one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with three equivalent Na(2)O5 trigonal bipyramids,  a cornercorner with one Na(4)O4 trigonal pyramid,  an edgeedge with one Mg(1)O4 tetrahedra,  an edgeedge with one Fe(1)O4 tetrahedra,  an edgeedge with one Na(2)O5 trigonal bipyramid, and edges with two equivalent Na(5)O5 trigonal bipyramids. The Na(6)-O(2) bond length is 2.79 Å. The Na(6)-O(3) bond length is 2.29 Å. The Na(6)-O(4) bond length is 2.54 Å. The Na(6)-O(7) bond length is 2.64 Å. The Na(6)-O(8) bond length is 2.53 Å. In the seventh Na site, Na(7) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(5), one O(6), and one O(7) atom. The Na(7)-O(3) bond length is 2.24 Å. The Na(7)-O(5) bond length is 2.42 Å. The Na(7)-O(6) bond length is 2.31 Å. The Na(7)-O(7) bond length is 2.38 Å. In the eighth Na site, Na(8) is bonded in a 3-coordinate geometry to one O(1), one O(2), one O(4), and one O(5) atom. The Na(8)-O(1) bond length is 2.30 Å. The Na(8)-O(2) bond length is 2.37 Å. The Na(8)-O(4) bond length is 2.73 Å. The Na(8)-O(5) bond length is 2.30 Å. Mg(1) is bonded to one O(1), one O(2), one O(4), and one O(8) atom to form MgO4 tetrahedra that share  a cornercorner with one Na(6)O5 square pyramid,  a cornercorner with one Fe(2)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid,  an edgeedge with one Na(6)O5 square pyramid,  an edgeedge with one Na(2)O5 trigonal bipyramid,  an edgeedge with one Na(5)O5 trigonal bipyramid, and  an edgeedge with one Na(4)O4 trigonal pyramid. The Mg(1)-O(1) bond length is 2.03 Å. The Mg(1)-O(2) bond length is 2.00 Å. The Mg(1)-O(4) bond length is 2.11 Å. The Mg(1)-O(8) bond length is 2.05 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Na(6)O5 square pyramid, corners with three equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid, corners with two equivalent Na(5)O5 trigonal bipyramids, corners with two equivalent Na(4)O4 trigonal pyramids,  an edgeedge with one Na(6)O5 square pyramid, and  an edgeedge with one Na(2)O5 trigonal bipyramid. The Fe(1)-O(2) bond length is 1.96 Å. The Fe(1)-O(4) bond length is 1.99 Å. The Fe(1)-O(5) bond length is 1.83 Å. The Fe(1)-O(8) bond length is 1.95 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with two equivalent Na(6)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Na(5)O5 trigonal bipyramid, corners with two equivalent Na(4)O4 trigonal pyramids,  an edgeedge with one Na(2)O5 trigonal bipyramid, and  an edgeedge with one Na(5)O5 trigonal bipyramid. The Fe(2)-O(1) bond length is 1.97 Å. The Fe(2)-O(3) bond length is 1.91 Å. The Fe(2)-O(6) bond length is 1.86 Å. The Fe(2)-O(7) bond length is 1.94 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), one Na(4), one Na(8), one Mg(1), and one Fe(2) atom to form distorted corner-sharing ONa3MgFe trigonal bipyramids. The corner-sharing octahedral tilt angles are 64°. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), one Na(4), one Na(6), one Na(8), one Mg(1), and one Fe(1) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), and one Fe(2) atom to form distorted corner-sharing ONa5Fe octahedra. In the fourth O site, O(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(8), one Mg(1), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Na(8), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(5), one Na(7), and one Fe(2) atom. In the seventh O site, O(7) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(5), one Na(6), one Na(7), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Mg(1), and one Fe(1) atom.