K3Fe5F15 crystallizes in the orthorhombic Pba2 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent F(2), two equivalent F(4), four equivalent F(7), and four equivalent F(8) atoms to form KF12 cuboctahedra that share faces with two equivalent K(1)F12 cuboctahedra, faces with four equivalent Fe(2)F6 octahedra, and faces with four equivalent Fe(3)F6 octahedra. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent F(3), two equivalent F(5), and two equivalent F(6) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent F(1), two equivalent F(5), and two equivalent F(6) atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedral tilt angles range from 0-35°. In the second Fe site, Fe(2) is bonded to one F(3), one F(6), one F(7), one F(8), and two equivalent F(2) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(1)F6 octahedra, corners with two equivalent Fe(2)F6 octahedra, corners with three equivalent Fe(3)F6 octahedra, and faces with two equivalent K(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-42°. In the third Fe site, Fe(3) is bonded to one F(3), one F(5), one F(7), one F(8), and two equivalent F(4) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(1)F6 octahedra, corners with two equivalent Fe(3)F6 octahedra, corners with three equivalent Fe(2)F6 octahedra, and faces with two equivalent K(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-42°. There are eight inequivalent F sites. In the first F site, F(6) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Fe(1), and one Fe(2) atom. In the second F site, F(7) is bonded in a distorted linear geometry to two equivalent K(1), one Fe(2), and one Fe(3) atom. In the third F site, F(8) is bonded in a distorted linear geometry to two equivalent K(1), one Fe(2), and one Fe(3) atom. In the fourth F site, F(1) is bonded in a linear geometry to two equivalent Fe(1) atoms. In the fifth F site, F(2) is bonded in a distorted linear geometry to one K(1) and two equivalent Fe(2) atoms. In the sixth F site, F(3) is bonded in a 4-coordinate geometry to two equivalent K(2), one Fe(2), and one Fe(3) atom. In the seventh F site, F(4) is bonded in a distorted linear geometry to one K(1) and two equivalent Fe(3) atoms. In the eighth F site, F(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Fe(1), and one Fe(3) atom.
K3Fe5F15 crystallizes in the orthorhombic Pba2 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent F(2), two equivalent F(4), four equivalent F(7), and four equivalent F(8) atoms to form KF12 cuboctahedra that share faces with two equivalent K(1)F12 cuboctahedra, faces with four equivalent Fe(2)F6 octahedra, and faces with four equivalent Fe(3)F6 octahedra. Both K(1)-F(2) bond lengths are 2.90 Å. Both K(1)-F(4) bond lengths are 2.88 Å. There are two shorter (2.87 Å) and two longer (2.90 Å) K(1)-F(7) bond lengths. There are two shorter (2.88 Å) and two longer (2.90 Å) K(1)-F(8) bond lengths. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent F(3), two equivalent F(5), and two equivalent F(6) atoms. There is one shorter (2.72 Å) and one longer (2.78 Å) K(2)-F(3) bond length. There is one shorter (2.92 Å) and one longer (3.05 Å) K(2)-F(5) bond length. There is one shorter (2.97 Å) and one longer (3.09 Å) K(2)-F(6) bond length. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent F(1), two equivalent F(5), and two equivalent F(6) atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedral tilt angles range from 0-35°. There is one shorter (2.00 Å) and one longer (2.02 Å) Fe(1)-F(1) bond length. Both Fe(1)-F(5) bond lengths are 1.93 Å. Both Fe(1)-F(6) bond lengths are 1.96 Å. In the second Fe site, Fe(2) is bonded to one F(3), one F(6), one F(7), one F(8), and two equivalent F(2) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(1)F6 octahedra, corners with two equivalent Fe(2)F6 octahedra, corners with three equivalent Fe(3)F6 octahedra, and faces with two equivalent K(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-42°. The Fe(2)-F(3) bond length is 2.02 Å. The Fe(2)-F(6) bond length is 2.06 Å. The Fe(2)-F(7) bond length is 2.02 Å. The Fe(2)-F(8) bond length is 2.02 Å. Both Fe(2)-F(2) bond lengths are 2.01 Å. In the third Fe site, Fe(3) is bonded to one F(3), one F(5), one F(7), one F(8), and two equivalent F(4) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(1)F6 octahedra, corners with two equivalent Fe(3)F6 octahedra, corners with three equivalent Fe(2)F6 octahedra, and faces with two equivalent K(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-42°. The Fe(3)-F(3) bond length is 2.13 Å. The Fe(3)-F(5) bond length is 2.12 Å. The Fe(3)-F(7) bond length is 2.15 Å. The Fe(3)-F(8) bond length is 2.15 Å. Both Fe(3)-F(4) bond lengths are 2.01 Å. There are eight inequivalent F sites. In the first F site, F(6) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Fe(1), and one Fe(2) atom. In the second F site, F(7) is bonded in a distorted linear geometry to two equivalent K(1), one Fe(2), and one Fe(3) atom. In the third F site, F(8) is bonded in a distorted linear geometry to two equivalent K(1), one Fe(2), and one Fe(3) atom. In the fourth F site, F(1) is bonded in a linear geometry to two equivalent Fe(1) atoms. In the fifth F site, F(2) is bonded in a distorted linear geometry to one K(1) and two equivalent Fe(2) atoms. In the sixth F site, F(3) is bonded in a 4-coordinate geometry to two equivalent K(2), one Fe(2), and one Fe(3) atom. In the seventh F site, F(4) is bonded in a distorted linear geometry to one K(1) and two equivalent Fe(3) atoms. In the eighth F site, F(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Fe(1), and one Fe(3) atom.