KCr(SO4)2 crystallizes in the trigonal P-3c1 space group. K(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form distorted KO12 cuboctahedra that share edges with six equivalent K(1)O12 cuboctahedra, edges with six equivalent S(1)O4 tetrahedra, and faces with two equivalent Cr(1)O6 octahedra. Cr(1) is bonded to six equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and faces with two equivalent K(1)O12 cuboctahedra. S(1) is bonded to one O(1) and three equivalent O(2) atoms to form SO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and edges with three equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 41°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent K(1) and one S(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Cr(1), and one S(1) atom.
KCr(SO4)2 crystallizes in the trigonal P-3c1 space group. K(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form distorted KO12 cuboctahedra that share edges with six equivalent K(1)O12 cuboctahedra, edges with six equivalent S(1)O4 tetrahedra, and faces with two equivalent Cr(1)O6 octahedra. All K(1)-O(1) bond lengths are 2.95 Å. All K(1)-O(2) bond lengths are 3.30 Å. Cr(1) is bonded to six equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and faces with two equivalent K(1)O12 cuboctahedra. All Cr(1)-O(2) bond lengths are 2.01 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 Cr(1)O6 octahedra and edges with three equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 41°. 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 distorted single-bond geometry to three equivalent K(1) and one S(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Cr(1), and one S(1) atom.