K4CrO4 crystallizes in the triclinic P-1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms. In the second K site, K(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), and two equivalent O(4) atoms. In the third K site, K(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(3) and two equivalent O(4) atoms. In the fourth K site, K(4) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted KO5 trigonal bipyramids that share corners with three equivalent Cr(1)O4 tetrahedra,  an edgeedge with one Cr(1)O4 tetrahedra, and edges with two equivalent K(4)O5 trigonal bipyramids. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share corners with three equivalent K(4)O5 trigonal bipyramids and  an edgeedge with one K(4)O5 trigonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one K(2), two equivalent K(1), two equivalent K(4), and one Cr(1) atom to form distorted edge-sharing OK5Cr octahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to one K(2), two equivalent K(1), two equivalent K(4), and one Cr(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(1), one K(2), one K(4), two equivalent K(3), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one K(1), two equivalent K(2), two equivalent K(3), and one Cr(1) atom.
K4CrO4 crystallizes in the triclinic P-1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms. The K(1)-O(3) bond length is 2.71 Å. The K(1)-O(4) bond length is 3.16 Å. There is one shorter (2.66 Å) and one longer (2.76 Å) K(1)-O(1) bond length. Both K(1)-O(2) bond lengths are 2.89 Å. In the second K site, K(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), and two equivalent O(4) atoms. The K(2)-O(1) bond length is 2.72 Å. The K(2)-O(2) bond length is 2.86 Å. The K(2)-O(3) bond length is 2.86 Å. There is one shorter (2.66 Å) and one longer (2.83 Å) K(2)-O(4) bond length. In the third K site, K(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(3) and two equivalent O(4) atoms. Both K(3)-O(3) bond lengths are 2.64 Å. There is one shorter (2.59 Å) and one longer (2.65 Å) K(3)-O(4) bond length. In the fourth K site, K(4) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted KO5 trigonal bipyramids that share corners with three equivalent Cr(1)O4 tetrahedra,  an edgeedge with one Cr(1)O4 tetrahedra, and edges with two equivalent K(4)O5 trigonal bipyramids. The K(4)-O(3) bond length is 2.77 Å. Both K(4)-O(1) bond lengths are 2.61 Å. There is one shorter (2.70 Å) and one longer (2.83 Å) K(4)-O(2) bond length. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share corners with three equivalent K(4)O5 trigonal bipyramids and  an edgeedge with one K(4)O5 trigonal bipyramid. The Cr(1)-O(1) bond length is 1.80 Å. The Cr(1)-O(2) bond length is 1.79 Å. The Cr(1)-O(3) bond length is 1.79 Å. The Cr(1)-O(4) bond length is 1.78 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one K(2), two equivalent K(1), two equivalent K(4), and one Cr(1) atom to form distorted edge-sharing OK5Cr octahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to one K(2), two equivalent K(1), two equivalent K(4), and one Cr(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(1), one K(2), one K(4), two equivalent K(3), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one K(1), two equivalent K(2), two equivalent K(3), and one Cr(1) atom.