Na4Fe6O13 crystallizes in the orthorhombic Iba2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(3), one O(5), two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to one O(2), one O(6), two equivalent O(4), two equivalent O(7), and three equivalent O(5) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O5 trigonal bipyramids, corners with two equivalent Fe(3)O5 trigonal bipyramids, and edges with three equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 18°. In the second Fe site, Fe(2) is bonded to one O(2), one O(5), two equivalent O(4), and two equivalent O(7) atoms to form FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  a cornercorner with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 2-6°. In the third Fe site, Fe(3) is bonded to one O(3), one O(5), and three equivalent O(6) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O5 trigonal bipyramids, corners with four equivalent Fe(3)O5 trigonal bipyramids, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 4°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Fe(1) atoms to form distorted OFe4 trigonal pyramids that share corners with four equivalent O(3)NaFe3 trigonal pyramids, edges with two equivalent O(1)Fe4 trigonal pyramids, and edges with two equivalent O(3)NaFe3 trigonal pyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded to one Na(1), one Fe(3), and two equivalent Fe(1) atoms to form distorted ONaFe3 trigonal pyramids that share corners with two equivalent O(4)Na4Fe2 octahedra, corners with two equivalent O(7)Na4Fe2 octahedra, corners with three equivalent O(6)NaFe3 tetrahedra, corners with two equivalent O(1)Fe4 trigonal pyramids, corners with two equivalent O(3)NaFe3 trigonal pyramids, and  an edgeedge with one O(1)Fe4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 28-69°. In the fourth O site, O(4) is bonded to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(2) atoms to form ONa4Fe2 octahedra that share corners with two equivalent O(7)Na4Fe2 octahedra, corners with two equivalent O(6)NaFe3 tetrahedra, corners with two equivalent O(3)NaFe3 trigonal pyramids, edges with two equivalent O(7)Na4Fe2 octahedra, faces with two equivalent O(4)Na4Fe2 octahedra, and faces with two equivalent O(7)Na4Fe2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), three equivalent Na(2), one Fe(2), and one Fe(3) atom. In the sixth O site, O(6) is bonded to one Na(2) and three equivalent Fe(3) atoms to form ONaFe3 tetrahedra that share corners with two equivalent O(4)Na4Fe2 octahedra, corners with two equivalent O(7)Na4Fe2 octahedra, corners with four equivalent O(6)NaFe3 tetrahedra, corners with three equivalent O(3)NaFe3 trigonal pyramids, and  an edgeedge with one O(6)NaFe3 tetrahedra. The corner-sharing octahedral tilt angles range from 33-65°. In the seventh O site, O(7) is bonded to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(2) atoms to form distorted ONa4Fe2 octahedra that share corners with two equivalent O(4)Na4Fe2 octahedra, corners with two equivalent O(6)NaFe3 tetrahedra, corners with two equivalent O(3)NaFe3 trigonal pyramids, edges with two equivalent O(4)Na4Fe2 octahedra, faces with two equivalent O(4)Na4Fe2 octahedra, and faces with two equivalent O(7)Na4Fe2 octahedra. The corner-sharing octahedral tilt angles are 2°.
Na4Fe6O13 crystallizes in the orthorhombic Iba2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(3), one O(5), two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. The Na(1)-O(3) bond length is 2.45 Å. The Na(1)-O(5) bond length is 2.71 Å. There is one shorter (2.58 Å) and one longer (2.76 Å) Na(1)-O(2) bond length. There is one shorter (2.48 Å) and one longer (2.50 Å) Na(1)-O(4) bond length. There is one shorter (2.47 Å) and one longer (2.59 Å) Na(1)-O(7) bond length. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to one O(2), one O(6), two equivalent O(4), two equivalent O(7), and three equivalent O(5) atoms. The Na(2)-O(2) bond length is 2.64 Å. The Na(2)-O(6) bond length is 2.37 Å. There is one shorter (2.43 Å) and one longer (2.49 Å) Na(2)-O(4) bond length. There is one shorter (2.58 Å) and one longer (2.63 Å) Na(2)-O(7) bond length. There are a spread of Na(2)-O(5) bond distances ranging from 2.53-2.72 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O5 trigonal bipyramids, corners with two equivalent Fe(3)O5 trigonal bipyramids, and edges with three equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 18°. The Fe(1)-O(2) bond length is 1.82 Å. There is one shorter (2.01 Å) and one longer (2.12 Å) Fe(1)-O(1) bond length. There is one shorter (2.00 Å) and one longer (2.03 Å) Fe(1)-O(3) bond length. In the second Fe site, Fe(2) is bonded to one O(2), one O(5), two equivalent O(4), and two equivalent O(7) atoms to form FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  a cornercorner with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 2-6°. The Fe(2)-O(2) bond length is 2.03 Å. The Fe(2)-O(5) bond length is 2.08 Å. Both Fe(2)-O(4) bond lengths are 1.90 Å. There is one shorter (1.88 Å) and one longer (1.89 Å) Fe(2)-O(7) bond length. In the third Fe site, Fe(3) is bonded to one O(3), one O(5), and three equivalent O(6) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O5 trigonal bipyramids, corners with four equivalent Fe(3)O5 trigonal bipyramids, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 4°. The Fe(3)-O(3) bond length is 1.95 Å. The Fe(3)-O(5) bond length is 1.79 Å. There are a spread of Fe(3)-O(6) bond distances ranging from 2.00-2.09 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Fe(1) atoms to form distorted OFe4 trigonal pyramids that share corners with four equivalent O(3)NaFe3 trigonal pyramids, edges with two equivalent O(1)Fe4 trigonal pyramids, and edges with two equivalent O(3)NaFe3 trigonal pyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded to one Na(1), one Fe(3), and two equivalent Fe(1) atoms to form distorted ONaFe3 trigonal pyramids that share corners with two equivalent O(4)Na4Fe2 octahedra, corners with two equivalent O(7)Na4Fe2 octahedra, corners with three equivalent O(6)NaFe3 tetrahedra, corners with two equivalent O(1)Fe4 trigonal pyramids, corners with two equivalent O(3)NaFe3 trigonal pyramids, and  an edgeedge with one O(1)Fe4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 28-69°. In the fourth O site, O(4) is bonded to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(2) atoms to form ONa4Fe2 octahedra that share corners with two equivalent O(7)Na4Fe2 octahedra, corners with two equivalent O(6)NaFe3 tetrahedra, corners with two equivalent O(3)NaFe3 trigonal pyramids, edges with two equivalent O(7)Na4Fe2 octahedra, faces with two equivalent O(4)Na4Fe2 octahedra, and faces with two equivalent O(7)Na4Fe2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), three equivalent Na(2), one Fe(2), and one Fe(3) atom. In the sixth O site, O(6) is bonded to one Na(2) and three equivalent Fe(3) atoms to form ONaFe3 tetrahedra that share corners with two equivalent O(4)Na4Fe2 octahedra, corners with two equivalent O(7)Na4Fe2 octahedra, corners with four equivalent O(6)NaFe3 tetrahedra, corners with three equivalent O(3)NaFe3 trigonal pyramids, and  an edgeedge with one O(6)NaFe3 tetrahedra. The corner-sharing octahedral tilt angles range from 33-65°. In the seventh O site, O(7) is bonded to two equivalent Na(1), two equivalent Na(2), and two equivalent Fe(2) atoms to form distorted ONa4Fe2 octahedra that share corners with two equivalent O(4)Na4Fe2 octahedra, corners with two equivalent O(6)NaFe3 tetrahedra, corners with two equivalent O(3)NaFe3 trigonal pyramids, edges with two equivalent O(4)Na4Fe2 octahedra, faces with two equivalent O(4)Na4Fe2 octahedra, and faces with two equivalent O(7)Na4Fe2 octahedra. The corner-sharing octahedral tilt angles are 2°.