K17Fe5O16 crystallizes in the monoclinic Cm space group. There are nine inequivalent K sites. In the first K site, K(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(8) atom. In the second K site, K(2) is bonded in a 4-coordinate geometry to one O(4), one O(7), and two equivalent O(6) atoms. In the third K site, K(3) is bonded in a 3-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. In the fourth K site, K(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(7) atom. In the fifth K site, K(5) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(5), one O(8), and one O(9) atom. In the sixth K site, K(6) is bonded in a 4-coordinate geometry to one O(5), one O(9), and two equivalent O(8) atoms. In the seventh K site, K(7) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(4), and two equivalent O(6) atoms. In the eighth K site, K(8) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(7) atom. In the ninth K site, K(9) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(5), one O(8), and one O(9) atom. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(5), one O(9), and two equivalent O(8) atoms to form corner-sharing FeO4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form corner-sharing FeO4 tetrahedra. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form corner-sharing FeO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one K(1), one K(3), one K(4), one K(5), one K(8), one K(9), and one Fe(3) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one K(1), one K(3), one K(4), one K(8), one Fe(2), and one Fe(3) atom. In the third O site, O(3) is bonded in a 7-coordinate geometry to one K(1), one K(3), one K(4), one K(5), one K(8), one K(9), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a 7-coordinate geometry to one K(2), one K(3), one K(4), one K(8), two equivalent K(7), and one Fe(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one K(6), two equivalent K(5), two equivalent K(9), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one K(3), two equivalent K(2), two equivalent K(7), and one Fe(2) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one K(2), one K(3), one K(4), one K(7), one K(8), and one Fe(2) atom. In the eighth O site, O(8) is bonded to one K(1), one K(5), one K(6), one K(9), one Fe(1), and one Fe(3) atom to form distorted edge-sharing OK4Fe2 octahedra. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one K(6), two equivalent K(5), two equivalent K(9), and one Fe(1) atom.
K17Fe5O16 crystallizes in the monoclinic Cm space group. There are nine inequivalent K sites. In the first K site, K(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(8) atom. The K(1)-O(1) bond length is 2.77 Å. The K(1)-O(2) bond length is 2.65 Å. The K(1)-O(3) bond length is 2.75 Å. The K(1)-O(8) bond length is 2.85 Å. In the second K site, K(2) is bonded in a 4-coordinate geometry to one O(4), one O(7), and two equivalent O(6) atoms. The K(2)-O(4) bond length is 2.68 Å. The K(2)-O(7) bond length is 2.59 Å. There is one shorter (2.55 Å) and one longer (2.66 Å) K(2)-O(6) bond length. In the third K site, K(3) is bonded in a 3-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. The K(3)-O(1) bond length is 3.16 Å. The K(3)-O(2) bond length is 3.10 Å. The K(3)-O(3) bond length is 3.14 Å. The K(3)-O(4) bond length is 2.77 Å. The K(3)-O(6) bond length is 2.62 Å. The K(3)-O(7) bond length is 2.78 Å. In the fourth K site, K(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(7) atom. The K(4)-O(1) bond length is 2.82 Å. The K(4)-O(2) bond length is 2.70 Å. The K(4)-O(3) bond length is 2.72 Å. The K(4)-O(4) bond length is 2.66 Å. The K(4)-O(7) bond length is 2.84 Å. In the fifth K site, K(5) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(5), one O(8), and one O(9) atom. The K(5)-O(1) bond length is 2.64 Å. The K(5)-O(3) bond length is 2.90 Å. The K(5)-O(5) bond length is 2.87 Å. The K(5)-O(8) bond length is 2.66 Å. The K(5)-O(9) bond length is 2.66 Å. In the sixth K site, K(6) is bonded in a 4-coordinate geometry to one O(5), one O(9), and two equivalent O(8) atoms. The K(6)-O(5) bond length is 2.77 Å. The K(6)-O(9) bond length is 2.75 Å. Both K(6)-O(8) bond lengths are 2.73 Å. In the seventh K site, K(7) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(4), and two equivalent O(6) atoms. The K(7)-O(7) bond length is 2.78 Å. There is one shorter (2.72 Å) and one longer (3.14 Å) K(7)-O(4) bond length. There is one shorter (2.72 Å) and one longer (2.88 Å) K(7)-O(6) bond length. In the eighth K site, K(8) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(7) atom. The K(8)-O(1) bond length is 2.65 Å. The K(8)-O(2) bond length is 2.68 Å. The K(8)-O(3) bond length is 2.76 Å. The K(8)-O(4) bond length is 2.97 Å. The K(8)-O(7) bond length is 2.69 Å. In the ninth K site, K(9) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(5), one O(8), and one O(9) atom. The K(9)-O(1) bond length is 2.91 Å. The K(9)-O(3) bond length is 2.65 Å. The K(9)-O(5) bond length is 2.65 Å. The K(9)-O(8) bond length is 2.66 Å. The K(9)-O(9) bond length is 2.86 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(5), one O(9), and two equivalent O(8) atoms to form corner-sharing FeO4 tetrahedra. The Fe(1)-O(5) bond length is 1.86 Å. The Fe(1)-O(9) bond length is 1.86 Å. Both Fe(1)-O(8) bond lengths are 1.92 Å. In the second Fe site, Fe(2) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form corner-sharing FeO4 tetrahedra. The Fe(2)-O(2) bond length is 1.98 Å. The Fe(2)-O(4) bond length is 1.88 Å. The Fe(2)-O(6) bond length is 1.88 Å. The Fe(2)-O(7) bond length is 1.87 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form corner-sharing FeO4 tetrahedra. The Fe(3)-O(1) bond length is 1.86 Å. The Fe(3)-O(2) bond length is 1.91 Å. The Fe(3)-O(3) bond length is 1.86 Å. The Fe(3)-O(8) bond length is 1.94 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one K(1), one K(3), one K(4), one K(5), one K(8), one K(9), and one Fe(3) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one K(1), one K(3), one K(4), one K(8), one Fe(2), and one Fe(3) atom. In the third O site, O(3) is bonded in a 7-coordinate geometry to one K(1), one K(3), one K(4), one K(5), one K(8), one K(9), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a 7-coordinate geometry to one K(2), one K(3), one K(4), one K(8), two equivalent K(7), and one Fe(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one K(6), two equivalent K(5), two equivalent K(9), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one K(3), two equivalent K(2), two equivalent K(7), and one Fe(2) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one K(2), one K(3), one K(4), one K(7), one K(8), and one Fe(2) atom. In the eighth O site, O(8) is bonded to one K(1), one K(5), one K(6), one K(9), one Fe(1), and one Fe(3) atom to form distorted edge-sharing OK4Fe2 octahedra. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one K(6), two equivalent K(5), two equivalent K(9), and one Fe(1) atom.