KCr2Al(HO4)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. Cr(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with two equivalent Al(1)H2O4 octahedra. The corner-sharing octahedral tilt angles are 40°. Al(1) is bonded to two equivalent H(1) and four equivalent O(3) atoms to form AlH2O4 octahedra that share corners with four equivalent Cr(1)O4 tetrahedra. H(1) is bonded in a single-bond geometry to one Al(1) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(1) and one Cr(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to two equivalent K(1) and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one K(1), one Cr(1), and one Al(1) atom.
KCr2Al(HO4)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. Both K(1)-O(1) bond lengths are 2.81 Å. All K(1)-O(2) bond lengths are 3.16 Å. All K(1)-O(3) bond lengths are 2.85 Å. Cr(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with two equivalent Al(1)H2O4 octahedra. The corner-sharing octahedral tilt angles are 40°. The Cr(1)-O(1) bond length is 1.62 Å. The Cr(1)-O(2) bond length is 1.62 Å. Both Cr(1)-O(3) bond lengths are 1.72 Å. Al(1) is bonded to two equivalent H(1) and four equivalent O(3) atoms to form AlH2O4 octahedra that share corners with four equivalent Cr(1)O4 tetrahedra. Both Al(1)-H(1) bond lengths are 1.98 Å. All Al(1)-O(3) bond lengths are 1.83 Å. H(1) is bonded in a single-bond geometry to one Al(1) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(1) and one Cr(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to two equivalent K(1) and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one K(1), one Cr(1), and one Al(1) atom.