Na4FeO5 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(7), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(8)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with two equivalent Fe(2)O5 square pyramids,  an edgeedge with one Na(8)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Na(7)O6 octahedra, and  an edgeedge with one Fe(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 24-29°. In the second Na site, Na(2) is bonded to one O(10), one O(2), one O(3), one O(4), one O(6), and one O(8) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(7)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Na(1)O6 octahedra,  an edgeedge with one Na(7)O6 octahedra, edges with two equivalent Na(8)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and  an edgeedge with one Fe(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 4-25°. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(8) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and one O(7) atom. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(6), one O(7), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(1), one O(5), one O(7), one O(8), and one O(9) atom. In the seventh Na site, Na(7) is bonded to one O(10), one O(2), one O(3), one O(5), one O(7), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with two equivalent Na(8)O6 octahedra,  a cornercorner with one Fe(2)O5 square pyramid,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, and edges with two equivalent Fe(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 11-26°. In the eighth Na site, Na(8) is bonded to one O(1), one O(10), one O(4), one O(6), one O(8), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Na(7)O6 octahedra,  a cornercorner with one Fe(2)O5 square pyramid,  an edgeedge with one Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-29°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(4), one O(6), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(8)O6 octahedra,  a cornercorner with one Fe(2)O5 square pyramid,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(7)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(5), one O(7), and one O(9) atom to form FeO5 square pyramids that share  a cornercorner with one Na(7)O6 octahedra,  a cornercorner with one Na(8)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Na(1)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra, and edges with two equivalent Na(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-72°. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(6), one Na(8), and one Fe(1) atom to form distorted corner-sharing ONa4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded to one Na(2), one Na(4), one Na(5), one Na(7), one Fe(1), and one Fe(2) atom to form corner-sharing ONa4Fe2 octahedra. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(7), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(8), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(6), one Na(7), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(5), one Na(8), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(4), 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(2), one Na(3), one Na(5), one Na(6), one Na(8), and one Fe(1) atom. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one Na(1), one Na(6), one Na(7), one Na(8), and one Fe(2) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(2), one Na(5), one Na(7), one Na(8), and one Fe(1) atom.
Na4FeO5 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(7), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(8)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with two equivalent Fe(2)O5 square pyramids,  an edgeedge with one Na(8)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Na(7)O6 octahedra, and  an edgeedge with one Fe(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 24-29°. The Na(1)-O(1) bond length is 2.36 Å. The Na(1)-O(3) bond length is 2.38 Å. The Na(1)-O(4) bond length is 2.42 Å. The Na(1)-O(5) bond length is 2.83 Å. The Na(1)-O(7) bond length is 2.35 Å. The Na(1)-O(9) bond length is 2.44 Å. In the second Na site, Na(2) is bonded to one O(10), one O(2), one O(3), one O(4), one O(6), and one O(8) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(7)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Na(1)O6 octahedra,  an edgeedge with one Na(7)O6 octahedra, edges with two equivalent Na(8)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and  an edgeedge with one Fe(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 4-25°. The Na(2)-O(10) bond length is 2.46 Å. The Na(2)-O(2) bond length is 2.35 Å. The Na(2)-O(3) bond length is 2.35 Å. The Na(2)-O(4) bond length is 2.36 Å. The Na(2)-O(6) bond length is 2.74 Å. The Na(2)-O(8) bond length is 2.33 Å. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(8) atom. The Na(3)-O(1) bond length is 2.31 Å. The Na(3)-O(4) bond length is 2.36 Å. The Na(3)-O(5) bond length is 2.41 Å. The Na(3)-O(6) bond length is 2.41 Å. The Na(3)-O(8) bond length is 2.44 Å. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and one O(7) atom. The Na(4)-O(2) bond length is 2.31 Å. The Na(4)-O(3) bond length is 2.32 Å. The Na(4)-O(5) bond length is 2.36 Å. The Na(4)-O(6) bond length is 2.29 Å. The Na(4)-O(7) bond length is 2.44 Å. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(6), one O(7), and one O(8) atom. The Na(5)-O(10) bond length is 2.35 Å. The Na(5)-O(2) bond length is 2.31 Å. The Na(5)-O(6) bond length is 2.45 Å. The Na(5)-O(7) bond length is 2.36 Å. The Na(5)-O(8) bond length is 2.29 Å. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(1), one O(5), one O(7), one O(8), and one O(9) atom. The Na(6)-O(1) bond length is 2.31 Å. The Na(6)-O(5) bond length is 2.43 Å. The Na(6)-O(7) bond length is 2.41 Å. The Na(6)-O(8) bond length is 2.41 Å. The Na(6)-O(9) bond length is 2.36 Å. In the seventh Na site, Na(7) is bonded to one O(10), one O(2), one O(3), one O(5), one O(7), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with two equivalent Na(8)O6 octahedra,  a cornercorner with one Fe(2)O5 square pyramid,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, and edges with two equivalent Fe(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 11-26°. The Na(7)-O(10) bond length is 2.36 Å. The Na(7)-O(2) bond length is 2.37 Å. The Na(7)-O(3) bond length is 2.40 Å. The Na(7)-O(5) bond length is 2.35 Å. The Na(7)-O(7) bond length is 2.88 Å. The Na(7)-O(9) bond length is 2.36 Å. In the eighth Na site, Na(8) is bonded to one O(1), one O(10), one O(4), one O(6), one O(8), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Na(7)O6 octahedra,  a cornercorner with one Fe(2)O5 square pyramid,  an edgeedge with one Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-29°. The Na(8)-O(1) bond length is 2.43 Å. The Na(8)-O(10) bond length is 2.41 Å. The Na(8)-O(4) bond length is 2.41 Å. The Na(8)-O(6) bond length is 2.38 Å. The Na(8)-O(8) bond length is 2.83 Å. The Na(8)-O(9) bond length is 2.40 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(4), one O(6), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(8)O6 octahedra,  a cornercorner with one Fe(2)O5 square pyramid,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(7)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. The Fe(1)-O(1) bond length is 1.86 Å. The Fe(1)-O(10) bond length is 1.83 Å. The Fe(1)-O(2) bond length is 1.98 Å. The Fe(1)-O(4) bond length is 1.84 Å. The Fe(1)-O(6) bond length is 1.87 Å. The Fe(1)-O(8) bond length is 1.89 Å. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(5), one O(7), and one O(9) atom to form FeO5 square pyramids that share  a cornercorner with one Na(7)O6 octahedra,  a cornercorner with one Na(8)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Na(1)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra, and edges with two equivalent Na(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-72°. The Fe(2)-O(2) bond length is 2.30 Å. The Fe(2)-O(3) bond length is 1.84 Å. The Fe(2)-O(5) bond length is 1.85 Å. The Fe(2)-O(7) bond length is 1.85 Å. The Fe(2)-O(9) bond length is 1.84 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(6), one Na(8), and one Fe(1) atom to form distorted corner-sharing ONa4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded to one Na(2), one Na(4), one Na(5), one Na(7), one Fe(1), and one Fe(2) atom to form corner-sharing ONa4Fe2 octahedra. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(7), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(8), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(6), one Na(7), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(5), one Na(8), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(4), 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(2), one Na(3), one Na(5), one Na(6), one Na(8), and one Fe(1) atom. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one Na(1), one Na(6), one Na(7), one Na(8), and one Fe(2) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(2), one Na(5), one Na(7), one Na(8), and one Fe(1) atom.