K3NaFeCl6 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 distorted hexagonal planar geometry to two equivalent Cl(2) and four equivalent Cl(1) atoms. In the second K site, K(2) is bonded in a distorted hexagonal planar geometry to two equivalent Cl(2) and four equivalent Cl(1) atoms. Na(1) is bonded to two equivalent Cl(2) and four equivalent Cl(1) atoms to form distorted NaCl6 octahedra that share faces with two equivalent Fe(1)Cl6 octahedra. Fe(1) is bonded to two equivalent Cl(2) and four equivalent Cl(1) atoms to form FeCl6 octahedra that share faces with two equivalent Na(1)Cl6 octahedra. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to one K(1), two equivalent K(2), one Na(1), and one Fe(1) atom to form a mixture of corner and face-sharing ClK3NaFe square pyramids. In the second Cl site, Cl(2) is bonded to one K(1), two equivalent K(2), one Na(1), and one Fe(1) atom to form a mixture of corner and face-sharing ClK3NaFe square pyramids.
K3NaFeCl6 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 distorted hexagonal planar geometry to two equivalent Cl(2) and four equivalent Cl(1) atoms. Both K(1)-Cl(2) bond lengths are 3.08 Å. All K(1)-Cl(1) bond lengths are 3.20 Å. In the second K site, K(2) is bonded in a distorted hexagonal planar geometry to two equivalent Cl(2) and four equivalent Cl(1) atoms. Both K(2)-Cl(2) bond lengths are 3.29 Å. There are two shorter (3.17 Å) and two longer (3.26 Å) K(2)-Cl(1) bond lengths. Na(1) is bonded to two equivalent Cl(2) and four equivalent Cl(1) atoms to form distorted NaCl6 octahedra that share faces with two equivalent Fe(1)Cl6 octahedra. Both Na(1)-Cl(2) bond lengths are 2.80 Å. All Na(1)-Cl(1) bond lengths are 2.91 Å. Fe(1) is bonded to two equivalent Cl(2) and four equivalent Cl(1) atoms to form FeCl6 octahedra that share faces with two equivalent Na(1)Cl6 octahedra. Both Fe(1)-Cl(2) bond lengths are 2.50 Å. All Fe(1)-Cl(1) bond lengths are 2.52 Å. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to one K(1), two equivalent K(2), one Na(1), and one Fe(1) atom to form a mixture of corner and face-sharing ClK3NaFe square pyramids. In the second Cl site, Cl(2) is bonded to one K(1), two equivalent K(2), one Na(1), and one Fe(1) atom to form a mixture of corner and face-sharing ClK3NaFe square pyramids.