CsFe(SO4)2 crystallizes in the trigonal P-3 space group. Cs(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. Fe(1) is bonded to six equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra. S(1) is bonded to one O(1) and three equivalent O(2) atoms to form SO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to three equivalent Cs(1) and one S(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(1) atom.
CsFe(SO4)2 crystallizes in the trigonal P-3 space group. Cs(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. All Cs(1)-O(1) bond lengths are 3.18 Å. Fe(1) is bonded to six equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra. All Fe(1)-O(2) bond lengths are 2.02 Å. S(1) is bonded to one O(1) and three equivalent O(2) atoms to form SO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 38°. The S(1)-O(1) bond length is 1.46 Å. All S(1)-O(2) bond lengths are 1.50 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to three equivalent Cs(1) and one S(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(1) atom.