Na5Fe11O16 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with six equivalent Fe(3)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the second Na site, Na(2) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form NaO6 octahedra that share corners with six equivalent Fe(3)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-6°. In the third Na site, Na(3) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-10°. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with three equivalent Na(3)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-10°. In the second Fe site, Fe(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with six equivalent Fe(5)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-8°. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form FeO6 octahedra that share corners with three equivalent Na(1)O6 octahedra, corners with three equivalent Na(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Fe(5)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(6)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the fifth Fe site, Fe(5) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(4)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the sixth Fe site, Fe(6) is bonded to two equivalent O(6) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Fe(1), one Fe(2), one Fe(3), and one Fe(5) atom to form ONa2Fe4 octahedra that share corners with three equivalent O(1)Na2Fe4 octahedra, corners with three equivalent O(2)NaFe5 octahedra,  an edgeedge with one O(5)Na2Fe4 octahedra,  an edgeedge with one O(6)Na2Fe4 octahedra,  an edgeedge with one O(2)NaFe5 octahedra, edges with three equivalent O(1)Na2Fe4 octahedra, edges with three equivalent O(3)Na2Fe4 octahedra, and edges with three equivalent O(4)Na3Fe3 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second O site, O(2) is bonded to one Na(2), one Fe(1), one Fe(3), one Fe(4), one Fe(5), and one Fe(6) atom to form ONaFe5 octahedra that share corners with three equivalent O(1)Na2Fe4 octahedra, corners with three equivalent O(2)NaFe5 octahedra,  an edgeedge with one O(1)Na2Fe4 octahedra,  an edgeedge with one O(3)Na2Fe4 octahedra,  an edgeedge with one O(4)Na3Fe3 octahedra, edges with three equivalent O(5)Na2Fe4 octahedra, edges with three equivalent O(6)Na2Fe4 octahedra, and edges with three equivalent O(2)NaFe5 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the third O site, O(3) is bonded to two equivalent Na(1), one Fe(2), one Fe(5), and two equivalent Fe(3) atoms to form ONa2Fe4 octahedra that share corners with three equivalent O(3)Na2Fe4 octahedra, corners with three equivalent O(5)Na2Fe4 octahedra,  an edgeedge with one O(6)Na2Fe4 octahedra, edges with two equivalent O(2)NaFe5 octahedra, edges with three equivalent O(4)Na3Fe3 octahedra, and edges with six equivalent O(1)Na2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Na(3), two equivalent Na(1), one Fe(1), and two equivalent Fe(3) atoms to form ONa3Fe3 octahedra that share corners with three equivalent O(6)Na2Fe4 octahedra, corners with three equivalent O(4)Na3Fe3 octahedra,  an edgeedge with one O(5)Na2Fe4 octahedra, edges with two equivalent O(2)NaFe5 octahedra, edges with three equivalent O(3)Na2Fe4 octahedra, and edges with six equivalent O(1)Na2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the fifth O site, O(5) is bonded to two equivalent Na(2), one Fe(4), one Fe(5), and two equivalent Fe(3) atoms to form ONa2Fe4 octahedra that share corners with three equivalent O(3)Na2Fe4 octahedra, corners with three equivalent O(5)Na2Fe4 octahedra,  an edgeedge with one O(4)Na3Fe3 octahedra, edges with two equivalent O(1)Na2Fe4 octahedra, edges with three equivalent O(6)Na2Fe4 octahedra, and edges with six equivalent O(2)NaFe5 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the sixth O site, O(6) is bonded to two equivalent Na(2), one Fe(1), one Fe(6), and two equivalent Fe(3) atoms to form ONa2Fe4 octahedra that share corners with three equivalent O(6)Na2Fe4 octahedra, corners with three equivalent O(4)Na3Fe3 octahedra,  an edgeedge with one O(3)Na2Fe4 octahedra, edges with two equivalent O(1)Na2Fe4 octahedra, edges with three equivalent O(5)Na2Fe4 octahedra, and edges with six equivalent O(2)NaFe5 octahedra. The corner-sharing octahedral tilt angles range from 0-5°.
Na5Fe11O16 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with six equivalent Fe(3)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. Both Na(1)-O(1) bond lengths are 2.31 Å. Both Na(1)-O(3) bond lengths are 2.29 Å. Both Na(1)-O(4) bond lengths are 2.33 Å. In the second Na site, Na(2) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form NaO6 octahedra that share corners with six equivalent Fe(3)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-6°. Both Na(2)-O(2) bond lengths are 2.24 Å. Both Na(2)-O(5) bond lengths are 2.29 Å. Both Na(2)-O(6) bond lengths are 2.29 Å. In the third Na site, Na(3) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-10°. Both Na(3)-O(4) bond lengths are 2.37 Å. All Na(3)-O(1) bond lengths are 2.31 Å. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with three equivalent Na(3)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-10°. The Fe(1)-O(4) bond length is 2.05 Å. The Fe(1)-O(6) bond length is 2.20 Å. Both Fe(1)-O(1) bond lengths are 2.07 Å. Both Fe(1)-O(2) bond lengths are 2.21 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with six equivalent Fe(5)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-8°. Both Fe(2)-O(3) bond lengths are 2.25 Å. All Fe(2)-O(1) bond lengths are 2.18 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form FeO6 octahedra that share corners with three equivalent Na(1)O6 octahedra, corners with three equivalent Na(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. The Fe(3)-O(1) bond length is 2.09 Å. The Fe(3)-O(2) bond length is 2.13 Å. The Fe(3)-O(3) bond length is 2.11 Å. The Fe(3)-O(4) bond length is 2.06 Å. The Fe(3)-O(5) bond length is 2.08 Å. The Fe(3)-O(6) bond length is 2.10 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Fe(5)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(6)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. Both Fe(4)-O(5) bond lengths are 2.24 Å. All Fe(4)-O(2) bond lengths are 2.14 Å. In the fifth Fe site, Fe(5) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(4)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. The Fe(5)-O(3) bond length is 2.15 Å. The Fe(5)-O(5) bond length is 2.14 Å. Both Fe(5)-O(1) bond lengths are 2.21 Å. Both Fe(5)-O(2) bond lengths are 2.23 Å. In the sixth Fe site, Fe(6) is bonded to two equivalent O(6) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. Both Fe(6)-O(6) bond lengths are 2.16 Å. All Fe(6)-O(2) bond lengths are 2.17 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Fe(1), one Fe(2), one Fe(3), and one Fe(5) atom to form ONa2Fe4 octahedra that share corners with three equivalent O(1)Na2Fe4 octahedra, corners with three equivalent O(2)NaFe5 octahedra,  an edgeedge with one O(5)Na2Fe4 octahedra,  an edgeedge with one O(6)Na2Fe4 octahedra,  an edgeedge with one O(2)NaFe5 octahedra, edges with three equivalent O(1)Na2Fe4 octahedra, edges with three equivalent O(3)Na2Fe4 octahedra, and edges with three equivalent O(4)Na3Fe3 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second O site, O(2) is bonded to one Na(2), one Fe(1), one Fe(3), one Fe(4), one Fe(5), and one Fe(6) atom to form ONaFe5 octahedra that share corners with three equivalent O(1)Na2Fe4 octahedra, corners with three equivalent O(2)NaFe5 octahedra,  an edgeedge with one O(1)Na2Fe4 octahedra,  an edgeedge with one O(3)Na2Fe4 octahedra,  an edgeedge with one O(4)Na3Fe3 octahedra, edges with three equivalent O(5)Na2Fe4 octahedra, edges with three equivalent O(6)Na2Fe4 octahedra, and edges with three equivalent O(2)NaFe5 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the third O site, O(3) is bonded to two equivalent Na(1), one Fe(2), one Fe(5), and two equivalent Fe(3) atoms to form ONa2Fe4 octahedra that share corners with three equivalent O(3)Na2Fe4 octahedra, corners with three equivalent O(5)Na2Fe4 octahedra,  an edgeedge with one O(6)Na2Fe4 octahedra, edges with two equivalent O(2)NaFe5 octahedra, edges with three equivalent O(4)Na3Fe3 octahedra, and edges with six equivalent O(1)Na2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Na(3), two equivalent Na(1), one Fe(1), and two equivalent Fe(3) atoms to form ONa3Fe3 octahedra that share corners with three equivalent O(6)Na2Fe4 octahedra, corners with three equivalent O(4)Na3Fe3 octahedra,  an edgeedge with one O(5)Na2Fe4 octahedra, edges with two equivalent O(2)NaFe5 octahedra, edges with three equivalent O(3)Na2Fe4 octahedra, and edges with six equivalent O(1)Na2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the fifth O site, O(5) is bonded to two equivalent Na(2), one Fe(4), one Fe(5), and two equivalent Fe(3) atoms to form ONa2Fe4 octahedra that share corners with three equivalent O(3)Na2Fe4 octahedra, corners with three equivalent O(5)Na2Fe4 octahedra,  an edgeedge with one O(4)Na3Fe3 octahedra, edges with two equivalent O(1)Na2Fe4 octahedra, edges with three equivalent O(6)Na2Fe4 octahedra, and edges with six equivalent O(2)NaFe5 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the sixth O site, O(6) is bonded to two equivalent Na(2), one Fe(1), one Fe(6), and two equivalent Fe(3) atoms to form ONa2Fe4 octahedra that share corners with three equivalent O(6)Na2Fe4 octahedra, corners with three equivalent O(4)Na3Fe3 octahedra,  an edgeedge with one O(3)Na2Fe4 octahedra, edges with two equivalent O(1)Na2Fe4 octahedra, edges with three equivalent O(5)Na2Fe4 octahedra, and edges with six equivalent O(2)NaFe5 octahedra. The corner-sharing octahedral tilt angles range from 0-5°.