K2FeF5 crystallizes in the monoclinic C2/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 10-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(3), and four equivalent F(4) atoms. In the second K site, K(2) is bonded in a 10-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(3), and four equivalent F(4) atoms. Fe(1) is bonded to one F(2), one F(3), two equivalent F(1), and two equivalent F(4) atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), and two equivalent Fe(1) atoms. In the second F site, F(2) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Fe(1) atom. In the third F site, F(3) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Fe(1) atom. In the fourth F site, F(4) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(2), and one Fe(1) atom.
K2FeF5 crystallizes in the monoclinic C2/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 10-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(3), and four equivalent F(4) atoms. Both K(1)-F(1) bond lengths are 2.92 Å. Both K(1)-F(2) bond lengths are 2.89 Å. There is one shorter (2.61 Å) and one longer (2.79 Å) K(1)-F(3) bond length. All K(1)-F(4) bond lengths are 2.75 Å. In the second K site, K(2) is bonded in a 10-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(3), and four equivalent F(4) atoms. Both K(2)-F(1) bond lengths are 2.99 Å. There is one shorter (2.63 Å) and one longer (2.81 Å) K(2)-F(2) bond length. Both K(2)-F(3) bond lengths are 2.89 Å. There are two shorter (2.70 Å) and two longer (2.79 Å) K(2)-F(4) bond lengths. Fe(1) is bonded to one F(2), one F(3), two equivalent F(1), and two equivalent F(4) atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedra are not tilted. The Fe(1)-F(2) bond length is 1.91 Å. The Fe(1)-F(3) bond length is 1.94 Å. Both Fe(1)-F(1) bond lengths are 2.02 Å. Both Fe(1)-F(4) bond lengths are 1.89 Å. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), and two equivalent Fe(1) atoms. In the second F site, F(2) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Fe(1) atom. In the third F site, F(3) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Fe(1) atom. In the fourth F site, F(4) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(2), and one Fe(1) atom.