The compound described by Fe21O23 crystallizes in the triclinic P1 space group. There are twenty-one inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(20), one O(22), one O(23), one O(3), one O(4), and one O(6) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the second Fe site, Fe(2) is bonded to one O(1), one O(21), one O(23), one O(4), one O(5), and one O(7) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(22), one O(5), one O(6), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the fourth Fe site, Fe(4) is bonded to one O(2), one O(23), one O(3), one O(6), one O(7), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-12°. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(10), one O(3), one O(4), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the sixth Fe site, Fe(6) is bonded to one O(11), one O(2), one O(4), one O(5), one O(8), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 5-13°. In the seventh Fe site, Fe(7) is bonded to one O(10), one O(12), one O(3), one O(5), one O(6), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-12°. In the eighth Fe site, Fe(8) is bonded to one O(10), one O(11), one O(13), one O(4), one O(6), and one O(7) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. In the ninth Fe site, Fe(9) is bonded to one O(11), one O(12), one O(14), one O(5), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-15°. In the tenth Fe site, Fe(10) is bonded to one O(12), one O(13), one O(15), one O(6), one O(8), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the eleventh Fe site, Fe(11) is bonded to one O(10), one O(11), one O(14), one O(15), one O(17), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 5-15°. In the twelfth Fe site, Fe(12) is bonded to one O(11), one O(12), one O(15), one O(16), one O(18), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-14°. In the thirteenth Fe site, Fe(13) is bonded to one O(10), one O(12), one O(13), one O(16), one O(17), and one O(19) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-15°. In the fourteenth Fe site, Fe(14) is bonded to one O(11), one O(13), one O(14), one O(17), one O(18), and one O(20) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the fifteenth Fe site, Fe(15) is bonded to one O(12), one O(14), one O(15), one O(18), one O(19), and one O(21) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-11°. In the sixteenth Fe site, Fe(16) is bonded to one O(13), one O(15), one O(16), one O(19), one O(20), and one O(22) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-14°. In the seventeenth Fe site, Fe(17) is bonded to one O(14), one O(16), one O(17), one O(20), one O(21), and one O(23) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the eighteenth Fe site, Fe(18) is bonded to one O(1), one O(15), one O(17), one O(18), one O(21), and one O(22) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the nineteenth Fe site, Fe(19) is bonded to one O(16), one O(18), one O(19), one O(2), one O(22), and one O(23) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-11°. In the twentieth Fe site, Fe(20) is bonded to one O(1), one O(17), one O(19), one O(20), one O(23), and one O(3) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. In the twenty-first Fe site, Fe(21) is bonded to one O(1), one O(18), one O(2), one O(20), one O(21), and one O(4) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-11°. There are twenty-three inequivalent O sites. In the first O site, O(1) is bonded to one Fe(18), one Fe(2), one Fe(20), one Fe(21), one Fe(3), and one Fe(5) atom to form OFe6 octahedra that share  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid, and  an edgeedge with one O(7)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 1-7°. In the second O site, O(2) is bonded to one Fe(19), one Fe(21), one Fe(3), one Fe(4), and one Fe(6) atom to form OFe5 square pyramids that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid, corners with two equivalent O(5)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(22)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 7-8°. In the third O site, O(3) is bonded to one Fe(1), one Fe(20), one Fe(4), one Fe(5), and one Fe(7) atom to form OFe5 square pyramids that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-6°. In the fourth O site, O(4) is bonded to one Fe(1), one Fe(2), one Fe(21), one Fe(5), one Fe(6), and one Fe(8) atom to form OFe6 octahedra that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid, and  an edgeedge with one O(7)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-7°. In the fifth O site, O(5) is bonded to one Fe(2), one Fe(3), one Fe(6), one Fe(7), and one Fe(9) atom to form OFe5 square pyramids that share  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid, corners with two equivalent O(2)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 7-10°. In the sixth O site, O(6) is bonded to one Fe(1), one Fe(10), one Fe(3), one Fe(4), one Fe(7), and one Fe(8) atom to form OFe6 octahedra that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-9°. In the seventh O site, O(7) is bonded to one Fe(2), one Fe(4), one Fe(5), one Fe(8), and one Fe(9) atom to form OFe5 square pyramids that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(10)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(3)Fe5 square pyramid, and  an edgeedge with one O(5)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 6-8°. In the eighth O site, O(8) is bonded to one Fe(10), one Fe(11), one Fe(3), one Fe(5), one Fe(6), and one Fe(9) atom to form OFe6 octahedra that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-6°. In the ninth O site, O(9) is bonded to one Fe(10), one Fe(12), one Fe(4), one Fe(6), and one Fe(7) atom to form OFe5 square pyramids that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid, and  an edgeedge with one O(5)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-8°. In the tenth O site, O(10) is bonded to one Fe(11), one Fe(13), one Fe(5), one Fe(7), and one Fe(8) atom to form OFe5 square pyramids that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(7)Fe5 square pyramids,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid, and  an edgeedge with one O(3)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-10°. In the eleventh O site, O(11) is bonded to one Fe(11), one Fe(12), one Fe(14), one Fe(6), one Fe(8), and one Fe(9) atom to form OFe6 octahedra that share  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-9°. In the twelfth O site, O(12) is bonded to one Fe(10), one Fe(12), one Fe(13), one Fe(15), one Fe(7), and one Fe(9) atom to form OFe6 octahedra that share  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-7°. In the thirteenth O site, O(13) is bonded to one Fe(10), one Fe(13), one Fe(14), one Fe(16), and one Fe(8) atom to form OFe5 square pyramids that share  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(16)Fe5 square pyramids,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid, and  an edgeedge with one O(19)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 3-5°. In the fourteenth O site, O(14) is bonded to one Fe(11), one Fe(14), one Fe(15), one Fe(17), and one Fe(9) atom to form OFe5 square pyramids that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra, and  an edgeedge with one O(21)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-10°. In the fifteenth O site, O(15) is bonded to one Fe(10), one Fe(11), one Fe(12), one Fe(15), one Fe(16), and one Fe(18) atom to form OFe6 octahedra that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 1-9°. In the sixteenth O site, O(16) is bonded to one Fe(12), one Fe(13), one Fe(16), one Fe(17), and one Fe(19) atom to form OFe5 square pyramids that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(13)Fe5 square pyramids,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(19)Fe5 square pyramid, and  an edgeedge with one O(22)Fe5 square pyramid. The corner-sharing octahedral tilt angles are 10°. In the seventeenth O site, O(17) is bonded to one Fe(11), one Fe(13), one Fe(14), one Fe(17), one Fe(18), and one Fe(20) atom to form OFe6 octahedra that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid, and  an edgeedge with one O(21)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-7°. In the eighteenth O site, O(18) is bonded to one Fe(12), one Fe(14), one Fe(15), one Fe(18), one Fe(19), and one Fe(21) atom to form OFe6 octahedra that share  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid, and  an edgeedge with one O(22)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-5°. In the nineteenth O site, O(19) is bonded to one Fe(13), one Fe(15), one Fe(16), one Fe(19), and one Fe(20) atom to form OFe5 square pyramids that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid, corners with two equivalent O(22)Fe5 square pyramids,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid, and  an edgeedge with one O(16)Fe5 square pyramid. The corner-sharing octahedral tilt angles are 6°. In the twentieth O site, O(20) is bonded to one Fe(1), one Fe(14), one Fe(16), one Fe(17), one Fe(20), and one Fe(21) atom to form OFe6 octahedra that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(2)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid, and  an edgeedge with one O(3)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-6°. In the twenty-first O site, O(21) is bonded to one Fe(15), one Fe(17), one Fe(18), one Fe(2), and one Fe(21) atom to form OFe5 square pyramids that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra, and  an edgeedge with one O(14)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 3-7°. In the twenty-second O site, O(22) is bonded to one Fe(1), one Fe(16), one Fe(18), one Fe(19), and one Fe(3) atom to form OFe5 square pyramids that share  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid, corners with two equivalent O(19)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(16)Fe5 square pyramid, and  an edgeedge with one O(2)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 8-10°. In the twenty-third O site, O(23) is bonded to one Fe(1), one Fe(17), one Fe(19), one Fe(2), one Fe(20), and one Fe(4) atom to form OFe6 octahedra that share  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid, and  an edgeedge with one O(7)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-5°. is represented by the CIF card [CIF]
data_Fe21O23
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.898
_cell_length_b   8.118
_cell_length_c   9.754
_cell_angle_alpha   83.086
_cell_angle_beta   73.556
_cell_angle_gamma   64.979
_symmetry_Int_Tables_number   1
_cell_volume   474.723
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Fe  Fe0  1  0.128  0.298  0.040  1.0
  Fe  Fe1  1  0.257  0.618  0.081  1.0
  Fe  Fe2  1  0.376  0.917  0.130  1.0
  Fe  Fe3  1  0.526  0.219  0.175  1.0
  Fe  Fe4  1  0.642  0.523  0.226  1.0
  Fe  Fe5  1  0.790  0.827  0.249  1.0
  Fe  Fe6  1  0.907  0.130  0.297  1.0
  Fe  Fe7  1  0.056  0.429  0.353  1.0
  Fe  Fe8  1  0.181  0.731  0.396  1.0
  Fe  Fe9  1  0.312  0.046  0.435  1.0
  Fe  Fe10  1  0.565  0.646  0.520  1.0
  Fe  Fe11  1  0.689  0.966  0.561  1.0
  Fe  Fe12  1  0.811  0.264  0.603  1.0
  Fe  Fe13  1  0.962  0.558  0.651  1.0
  Fe  Fe14  1  0.089  0.873  0.704  1.0
  Fe  Fe15  1  0.218  0.177  0.738  1.0
  Fe  Fe16  1  0.350  0.472  0.777  1.0
  Fe  Fe17  1  0.469  0.785  0.829  1.0
  Fe  Fe18  1  0.616  0.087  0.874  1.0
  Fe  Fe19  1  0.748  0.383  0.915  1.0
  Fe  Fe20  1  0.873  0.700  0.959  1.0
  O  O21  1  0.572  0.648  0.021  1.0
  O  O22  1  0.669  0.965  0.066  1.0
  O  O23  1  0.821  0.266  0.124  1.0
  O  O24  1  0.967  0.557  0.155  1.0
  O  O25  1  0.090  0.874  0.212  1.0
  O  O26  1  0.197  0.184  0.247  1.0
  O  O27  1  0.330  0.480  0.273  1.0
  O  O28  1  0.478  0.790  0.327  1.0
  O  O29  1  0.635  0.074  0.364  1.0
  O  O30  1  0.772  0.383  0.403  1.0
  O  O31  1  0.872  0.679  0.451  1.0
  O  O32  1  0.002  0.995  0.500  1.0
  O  O33  1  0.119  0.304  0.541  1.0
  O  O34  1  0.247  0.636  0.598  1.0
  O  O35  1  0.375  0.915  0.635  1.0
  O  O36  1  0.525  0.201  0.693  1.0
  O  O37  1  0.650  0.529  0.720  1.0
  O  O38  1  0.789  0.835  0.758  1.0
  O  O39  1  0.906  0.128  0.792  1.0
  O  O40  1  0.041  0.435  0.847  1.0
  O  O41  1  0.170  0.735  0.882  1.0
  O  O42  1  0.330  0.050  0.929  1.0
  O  O43  1  0.445  0.341  0.971  1.0
[/CIF]
.
The compound described by Fe21O23 crystallizes in the triclinic P1 space group. There are twenty-one inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(20), one O(22), one O(23), one O(3), one O(4), and one O(6) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the second Fe site, Fe(2) is bonded to one O(1), one O(21), one O(23), one O(4), one O(5), and one O(7) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(22), one O(5), one O(6), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the fourth Fe site, Fe(4) is bonded to one O(2), one O(23), one O(3), one O(6), one O(7), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-12°. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(10), one O(3), one O(4), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the sixth Fe site, Fe(6) is bonded to one O(11), one O(2), one O(4), one O(5), one O(8), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 5-13°. In the seventh Fe site, Fe(7) is bonded to one O(10), one O(12), one O(3), one O(5), one O(6), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-12°. In the eighth Fe site, Fe(8) is bonded to one O(10), one O(11), one O(13), one O(4), one O(6), and one O(7) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. In the ninth Fe site, Fe(9) is bonded to one O(11), one O(12), one O(14), one O(5), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-15°. In the tenth Fe site, Fe(10) is bonded to one O(12), one O(13), one O(15), one O(6), one O(8), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the eleventh Fe site, Fe(11) is bonded to one O(10), one O(11), one O(14), one O(15), one O(17), and one O(8) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 5-15°. In the twelfth Fe site, Fe(12) is bonded to one O(11), one O(12), one O(15), one O(16), one O(18), and one O(9) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-14°. In the thirteenth Fe site, Fe(13) is bonded to one O(10), one O(12), one O(13), one O(16), one O(17), and one O(19) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-15°. In the fourteenth Fe site, Fe(14) is bonded to one O(11), one O(13), one O(14), one O(17), one O(18), and one O(20) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the fifteenth Fe site, Fe(15) is bonded to one O(12), one O(14), one O(15), one O(18), one O(19), and one O(21) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-11°. In the sixteenth Fe site, Fe(16) is bonded to one O(13), one O(15), one O(16), one O(19), one O(20), and one O(22) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-14°. In the seventeenth Fe site, Fe(17) is bonded to one O(14), one O(16), one O(17), one O(20), one O(21), and one O(23) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the eighteenth Fe site, Fe(18) is bonded to one O(1), one O(15), one O(17), one O(18), one O(21), and one O(22) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the nineteenth Fe site, Fe(19) is bonded to one O(16), one O(18), one O(19), one O(2), one O(22), and one O(23) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 1-11°. In the twentieth Fe site, Fe(20) is bonded to one O(1), one O(17), one O(19), one O(20), one O(23), and one O(3) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 3-11°. In the twenty-first Fe site, Fe(21) is bonded to one O(1), one O(18), one O(2), one O(20), one O(21), and one O(4) atom to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 2-11°. There are twenty-three inequivalent O sites. In the first O site, O(1) is bonded to one Fe(18), one Fe(2), one Fe(20), one Fe(21), one Fe(3), and one Fe(5) atom to form OFe6 octahedra that share  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid, and  an edgeedge with one O(7)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 1-7°. In the second O site, O(2) is bonded to one Fe(19), one Fe(21), one Fe(3), one Fe(4), and one Fe(6) atom to form OFe5 square pyramids that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid, corners with two equivalent O(5)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(22)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 7-8°. In the third O site, O(3) is bonded to one Fe(1), one Fe(20), one Fe(4), one Fe(5), and one Fe(7) atom to form OFe5 square pyramids that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-6°. In the fourth O site, O(4) is bonded to one Fe(1), one Fe(2), one Fe(21), one Fe(5), one Fe(6), and one Fe(8) atom to form OFe6 octahedra that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid, and  an edgeedge with one O(7)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-7°. In the fifth O site, O(5) is bonded to one Fe(2), one Fe(3), one Fe(6), one Fe(7), and one Fe(9) atom to form OFe5 square pyramids that share  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid, corners with two equivalent O(2)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 7-10°. In the sixth O site, O(6) is bonded to one Fe(1), one Fe(10), one Fe(3), one Fe(4), one Fe(7), and one Fe(8) atom to form OFe6 octahedra that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-9°. In the seventh O site, O(7) is bonded to one Fe(2), one Fe(4), one Fe(5), one Fe(8), and one Fe(9) atom to form OFe5 square pyramids that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(10)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(3)Fe5 square pyramid, and  an edgeedge with one O(5)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 6-8°. In the eighth O site, O(8) is bonded to one Fe(10), one Fe(11), one Fe(3), one Fe(5), one Fe(6), and one Fe(9) atom to form OFe6 octahedra that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-6°. In the ninth O site, O(9) is bonded to one Fe(10), one Fe(12), one Fe(4), one Fe(6), and one Fe(7) atom to form OFe5 square pyramids that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid, and  an edgeedge with one O(5)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-8°. In the tenth O site, O(10) is bonded to one Fe(11), one Fe(13), one Fe(5), one Fe(7), and one Fe(8) atom to form OFe5 square pyramids that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(7)Fe5 square pyramids,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid, and  an edgeedge with one O(3)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-10°. In the eleventh O site, O(11) is bonded to one Fe(11), one Fe(12), one Fe(14), one Fe(6), one Fe(8), and one Fe(9) atom to form OFe6 octahedra that share  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid,  an edgeedge with one O(7)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-9°. In the twelfth O site, O(12) is bonded to one Fe(10), one Fe(12), one Fe(13), one Fe(15), one Fe(7), and one Fe(9) atom to form OFe6 octahedra that share  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(5)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-7°. In the thirteenth O site, O(13) is bonded to one Fe(10), one Fe(13), one Fe(14), one Fe(16), and one Fe(8) atom to form OFe5 square pyramids that share  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(16)Fe5 square pyramids,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid, and  an edgeedge with one O(19)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 3-5°. In the fourteenth O site, O(14) is bonded to one Fe(11), one Fe(14), one Fe(15), one Fe(17), and one Fe(9) atom to form OFe5 square pyramids that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra, and  an edgeedge with one O(21)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-10°. In the fifteenth O site, O(15) is bonded to one Fe(10), one Fe(11), one Fe(12), one Fe(15), one Fe(16), and one Fe(18) atom to form OFe6 octahedra that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(8)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid, and  an edgeedge with one O(9)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 1-9°. In the sixteenth O site, O(16) is bonded to one Fe(12), one Fe(13), one Fe(16), one Fe(17), and one Fe(19) atom to form OFe5 square pyramids that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid, corners with two equivalent O(13)Fe5 square pyramids,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(19)Fe5 square pyramid, and  an edgeedge with one O(22)Fe5 square pyramid. The corner-sharing octahedral tilt angles are 10°. In the seventeenth O site, O(17) is bonded to one Fe(11), one Fe(13), one Fe(14), one Fe(17), one Fe(18), and one Fe(20) atom to form OFe6 octahedra that share  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(10)Fe5 square pyramid,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid, and  an edgeedge with one O(21)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 5-7°. In the eighteenth O site, O(18) is bonded to one Fe(12), one Fe(14), one Fe(15), one Fe(18), one Fe(19), and one Fe(21) atom to form OFe6 octahedra that share  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(11)Fe6 octahedra,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid, and  an edgeedge with one O(22)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-5°. In the nineteenth O site, O(19) is bonded to one Fe(13), one Fe(15), one Fe(16), one Fe(19), and one Fe(20) atom to form OFe5 square pyramids that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(10)Fe5 square pyramid,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid, corners with two equivalent O(22)Fe5 square pyramids,  an edgeedge with one O(12)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid, and  an edgeedge with one O(16)Fe5 square pyramid. The corner-sharing octahedral tilt angles are 6°. In the twentieth O site, O(20) is bonded to one Fe(1), one Fe(14), one Fe(16), one Fe(17), one Fe(20), and one Fe(21) atom to form OFe6 octahedra that share  a cornercorner with one O(11)Fe6 octahedra,  a cornercorner with one O(15)Fe6 octahedra,  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(23)Fe6 octahedra,  a cornercorner with one O(6)Fe6 octahedra,  a cornercorner with one O(2)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(13)Fe5 square pyramid,  an edgeedge with one O(14)Fe5 square pyramid,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid, and  an edgeedge with one O(3)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 2-6°. In the twenty-first O site, O(21) is bonded to one Fe(15), one Fe(17), one Fe(18), one Fe(2), and one Fe(21) atom to form OFe5 square pyramids that share  a cornercorner with one O(1)Fe6 octahedra,  a cornercorner with one O(12)Fe6 octahedra,  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(16)Fe5 square pyramid,  a cornercorner with one O(19)Fe5 square pyramid,  a cornercorner with one O(2)Fe5 square pyramid,  a cornercorner with one O(22)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(7)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra, and  an edgeedge with one O(14)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 3-7°. In the twenty-second O site, O(22) is bonded to one Fe(1), one Fe(16), one Fe(18), one Fe(19), and one Fe(3) atom to form OFe5 square pyramids that share  a cornercorner with one O(17)Fe6 octahedra,  a cornercorner with one O(4)Fe6 octahedra,  a cornercorner with one O(8)Fe6 octahedra,  a cornercorner with one O(13)Fe5 square pyramid,  a cornercorner with one O(21)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid, corners with two equivalent O(19)Fe5 square pyramids,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(15)Fe6 octahedra,  an edgeedge with one O(18)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(23)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(16)Fe5 square pyramid, and  an edgeedge with one O(2)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 8-10°. In the twenty-third O site, O(23) is bonded to one Fe(1), one Fe(17), one Fe(19), one Fe(2), one Fe(20), and one Fe(4) atom to form OFe6 octahedra that share  a cornercorner with one O(18)Fe6 octahedra,  a cornercorner with one O(20)Fe6 octahedra,  a cornercorner with one O(14)Fe5 square pyramid,  a cornercorner with one O(3)Fe5 square pyramid,  a cornercorner with one O(5)Fe5 square pyramid,  a cornercorner with one O(9)Fe5 square pyramid,  an edgeedge with one O(1)Fe6 octahedra,  an edgeedge with one O(17)Fe6 octahedra,  an edgeedge with one O(20)Fe6 octahedra,  an edgeedge with one O(4)Fe6 octahedra,  an edgeedge with one O(6)Fe6 octahedra,  an edgeedge with one O(16)Fe5 square pyramid,  an edgeedge with one O(19)Fe5 square pyramid,  an edgeedge with one O(2)Fe5 square pyramid,  an edgeedge with one O(21)Fe5 square pyramid,  an edgeedge with one O(22)Fe5 square pyramid,  an edgeedge with one O(3)Fe5 square pyramid, and  an edgeedge with one O(7)Fe5 square pyramid. The corner-sharing octahedral tilt angles range from 4-5°. is represented by the CIF card [CIF]
data_Fe21O23
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.898
_cell_length_b   8.118
_cell_length_c   9.754
_cell_angle_alpha   83.086
_cell_angle_beta   73.556
_cell_angle_gamma   64.979
_symmetry_Int_Tables_number   1
_cell_volume   474.723
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Fe  Fe0  1  0.128  0.298  0.040  1.0
  Fe  Fe1  1  0.257  0.618  0.081  1.0
  Fe  Fe2  1  0.376  0.917  0.130  1.0
  Fe  Fe3  1  0.526  0.219  0.175  1.0
  Fe  Fe4  1  0.642  0.523  0.226  1.0
  Fe  Fe5  1  0.790  0.827  0.249  1.0
  Fe  Fe6  1  0.907  0.130  0.297  1.0
  Fe  Fe7  1  0.056  0.429  0.353  1.0
  Fe  Fe8  1  0.181  0.731  0.396  1.0
  Fe  Fe9  1  0.312  0.046  0.435  1.0
  Fe  Fe10  1  0.565  0.646  0.520  1.0
  Fe  Fe11  1  0.689  0.966  0.561  1.0
  Fe  Fe12  1  0.811  0.264  0.603  1.0
  Fe  Fe13  1  0.962  0.558  0.651  1.0
  Fe  Fe14  1  0.089  0.873  0.704  1.0
  Fe  Fe15  1  0.218  0.177  0.738  1.0
  Fe  Fe16  1  0.350  0.472  0.777  1.0
  Fe  Fe17  1  0.469  0.785  0.829  1.0
  Fe  Fe18  1  0.616  0.087  0.874  1.0
  Fe  Fe19  1  0.748  0.383  0.915  1.0
  Fe  Fe20  1  0.873  0.700  0.959  1.0
  O  O21  1  0.572  0.648  0.021  1.0
  O  O22  1  0.669  0.965  0.066  1.0
  O  O23  1  0.821  0.266  0.124  1.0
  O  O24  1  0.967  0.557  0.155  1.0
  O  O25  1  0.090  0.874  0.212  1.0
  O  O26  1  0.197  0.184  0.247  1.0
  O  O27  1  0.330  0.480  0.273  1.0
  O  O28  1  0.478  0.790  0.327  1.0
  O  O29  1  0.635  0.074  0.364  1.0
  O  O30  1  0.772  0.383  0.403  1.0
  O  O31  1  0.872  0.679  0.451  1.0
  O  O32  1  0.002  0.995  0.500  1.0
  O  O33  1  0.119  0.304  0.541  1.0
  O  O34  1  0.247  0.636  0.598  1.0
  O  O35  1  0.375  0.915  0.635  1.0
  O  O36  1  0.525  0.201  0.693  1.0
  O  O37  1  0.650  0.529  0.720  1.0
  O  O38  1  0.789  0.835  0.758  1.0
  O  O39  1  0.906  0.128  0.792  1.0
  O  O40  1  0.041  0.435  0.847  1.0
  O  O41  1  0.170  0.735  0.882  1.0
  O  O42  1  0.330  0.050  0.929  1.0
  O  O43  1  0.445  0.341  0.971  1.0
[/CIF]
.