K2Cu3(As2O6)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 9-coordinate geometry to three equivalent O(4) and six equivalent O(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form CuO5 square pyramids that share corners with three equivalent As(1)O4 tetrahedra and  an edgeedge with one Cu(2)O4 octahedra. In the second Cu site, Cu(2) is bonded to four equivalent O(2) atoms to form distorted edge-sharing CuO4 octahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form AsO4 tetrahedra that share corners with three equivalent Cu(1)O5 square pyramids. In the second As site, As(2) is bonded in a distorted trigonal non-coplanar geometry to one O(3) and two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to three equivalent K(1), one Cu(1), and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one As(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one As(1) and one As(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent K(1), one Cu(1), and one As(1) atom.
K2Cu3(As2O6)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 9-coordinate geometry to three equivalent O(4) and six equivalent O(1) atoms. There are two shorter (2.83 Å) and one longer (3.08 Å) K(1)-O(4) bond length. There are a spread of K(1)-O(1) bond distances ranging from 2.89-3.13 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form CuO5 square pyramids that share corners with three equivalent As(1)O4 tetrahedra and  an edgeedge with one Cu(2)O4 octahedra. The Cu(1)-O(4) bond length is 2.44 Å. Both Cu(1)-O(1) bond lengths are 1.96 Å. Both Cu(1)-O(2) bond lengths are 2.00 Å. In the second Cu site, Cu(2) is bonded to four equivalent O(2) atoms to form distorted edge-sharing CuO4 octahedra. All Cu(2)-O(2) bond lengths are 1.98 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form AsO4 tetrahedra that share corners with three equivalent Cu(1)O5 square pyramids. The As(1)-O(3) bond length is 1.80 Å. The As(1)-O(4) bond length is 1.69 Å. Both As(1)-O(1) bond lengths are 1.72 Å. In the second As site, As(2) is bonded in a distorted trigonal non-coplanar geometry to one O(3) and two equivalent O(2) atoms. The As(2)-O(3) bond length is 1.86 Å. Both As(2)-O(2) bond lengths are 1.81 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to three equivalent K(1), one Cu(1), and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one As(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one As(1) and one As(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent K(1), one Cu(1), and one As(1) atom.