KCr2FeO8 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 10-coordinate geometry to four equivalent O(3) and six equivalent O(1) 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 three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-42°. Fe(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Cr(1)O4 tetrahedra. There are three 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 Cr(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Cr(1), and one Fe(1) atom.
KCr2FeO8 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 10-coordinate geometry to four equivalent O(3) and six equivalent O(1) atoms. All K(1)-O(3) bond lengths are 2.87 Å. There are two shorter (2.95 Å) and four longer (3.31 Å) K(1)-O(1) bond lengths. 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 three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-42°. The Cr(1)-O(1) bond length is 1.62 Å. The Cr(1)-O(2) bond length is 1.66 Å. Both Cr(1)-O(3) bond lengths are 1.69 Å. Fe(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Cr(1)O4 tetrahedra. Both Fe(1)-O(2) bond lengths are 2.01 Å. All Fe(1)-O(3) bond lengths are 2.02 Å. There are three 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 Cr(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one Fe(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Cr(1), and one Fe(1) atom.