Cs2NaFeF6 crystallizes in the trigonal R-3m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to three equivalent F(2) and nine equivalent F(1) atoms to form distorted CsF12 cuboctahedra that share corners with three equivalent Cs(2)F12 cuboctahedra, corners with six equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Na(1)F6 octahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with four equivalent Cs(2)F12 cuboctahedra,  a faceface with one Fe(1)F6 octahedra, faces with three equivalent Na(1)F6 octahedra, and faces with three equivalent Fe(2)F6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second Cs site, Cs(2) is bonded to three equivalent F(1) and nine equivalent F(2) atoms to form distorted CsF12 cuboctahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with six equivalent Cs(2)F12 cuboctahedra, corners with three equivalent Fe(2)F6 octahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with four equivalent Cs(1)F12 cuboctahedra, faces with three equivalent Fe(1)F6 octahedra, and faces with four equivalent Na(1)F6 octahedra. The corner-sharing octahedral tilt angles are 12°. Na(1) is bonded to three equivalent F(1) and three equivalent F(2) atoms to form distorted NaF6 octahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Fe(1)F6 octahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with four equivalent Cs(2)F12 cuboctahedra, and  a faceface with one Fe(2)F6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to six equivalent F(2) atoms to form FeF6 octahedra that share corners with six equivalent Na(1)F6 octahedra, faces with two equivalent Cs(1)F12 cuboctahedra, and faces with six equivalent Cs(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. In the second Fe site, Fe(2) is bonded to six equivalent F(1) atoms to form FeF6 octahedra that share corners with six equivalent Cs(2)F12 cuboctahedra, faces with six equivalent Cs(1)F12 cuboctahedra, and faces with two equivalent Na(1)F6 octahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 6-coordinate geometry to one Cs(2), three equivalent Cs(1), one Na(1), and one Fe(2) atom. In the second F site, F(2) is bonded in a distorted linear geometry to one Cs(1), three equivalent Cs(2), one Na(1), and one Fe(1) atom.
Cs2NaFeF6 crystallizes in the trigonal R-3m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to three equivalent F(2) and nine equivalent F(1) atoms to form distorted CsF12 cuboctahedra that share corners with three equivalent Cs(2)F12 cuboctahedra, corners with six equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Na(1)F6 octahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with four equivalent Cs(2)F12 cuboctahedra,  a faceface with one Fe(1)F6 octahedra, faces with three equivalent Na(1)F6 octahedra, and faces with three equivalent Fe(2)F6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Cs(1)-F(2) bond lengths are 3.26 Å. There are three shorter (3.19 Å) and six longer (3.20 Å) Cs(1)-F(1) bond lengths. In the second Cs site, Cs(2) is bonded to three equivalent F(1) and nine equivalent F(2) atoms to form distorted CsF12 cuboctahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with six equivalent Cs(2)F12 cuboctahedra, corners with three equivalent Fe(2)F6 octahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with four equivalent Cs(1)F12 cuboctahedra, faces with three equivalent Fe(1)F6 octahedra, and faces with four equivalent Na(1)F6 octahedra. The corner-sharing octahedral tilt angles are 12°. All Cs(2)-F(1) bond lengths are 3.20 Å. There are six shorter (3.23 Å) and three longer (3.41 Å) Cs(2)-F(2) bond lengths. Na(1) is bonded to three equivalent F(1) and three equivalent F(2) atoms to form distorted NaF6 octahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Fe(1)F6 octahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with four equivalent Cs(2)F12 cuboctahedra, and  a faceface with one Fe(2)F6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Na(1)-F(1) bond lengths are 2.42 Å. All Na(1)-F(2) bond lengths are 2.29 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to six equivalent F(2) atoms to form FeF6 octahedra that share corners with six equivalent Na(1)F6 octahedra, faces with two equivalent Cs(1)F12 cuboctahedra, and faces with six equivalent Cs(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. All Fe(1)-F(2) bond lengths are 1.98 Å. In the second Fe site, Fe(2) is bonded to six equivalent F(1) atoms to form FeF6 octahedra that share corners with six equivalent Cs(2)F12 cuboctahedra, faces with six equivalent Cs(1)F12 cuboctahedra, and faces with two equivalent Na(1)F6 octahedra. All Fe(2)-F(1) bond lengths are 1.96 Å. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 6-coordinate geometry to one Cs(2), three equivalent Cs(1), one Na(1), and one Fe(2) atom. In the second F site, F(2) is bonded in a distorted linear geometry to one Cs(1), three equivalent Cs(2), one Na(1), and one Fe(1) atom.