Cs2K2Cd3O5 crystallizes in the triclinic P-1 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 3-coordinate geometry to one O(2) and two equivalent O(4) atoms. In the second Cs site, Cs(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), and two equivalent O(3) atoms. In the second K site, K(2) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form distorted KO5 trigonal bipyramids that share  a cornercorner with one Cd(3)O4 tetrahedra, corners with two equivalent Cd(2)O4 tetrahedra, corners with two equivalent Cd(1)O4 trigonal pyramids,  an edgeedge with one Cd(2)O4 tetrahedra, edges with two equivalent Cd(3)O4 tetrahedra, and edges with two equivalent K(2)O5 trigonal bipyramids. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form distorted CdO4 trigonal pyramids that share  a cornercorner with one Cd(2)O4 tetrahedra,  a cornercorner with one Cd(3)O4 tetrahedra, corners with two equivalent K(2)O5 trigonal bipyramids,  an edgeedge with one Cd(3)O4 tetrahedra, and  an edgeedge with one Cd(1)O4 trigonal pyramid. In the second Cd site, Cd(2) is bonded to one O(1), one O(4), and two equivalent O(5) atoms to form distorted CdO4 tetrahedra that share corners with three equivalent Cd(3)O4 tetrahedra, corners with two equivalent K(2)O5 trigonal bipyramids,  a cornercorner with one Cd(1)O4 trigonal pyramid,  an edgeedge with one Cd(2)O4 tetrahedra, and  an edgeedge with one K(2)O5 trigonal bipyramid. In the third Cd site, Cd(3) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form CdO4 tetrahedra that share corners with three equivalent Cd(2)O4 tetrahedra,  a cornercorner with one K(2)O5 trigonal bipyramid,  a cornercorner with one Cd(1)O4 trigonal pyramid, edges with two equivalent K(2)O5 trigonal bipyramids, and  an edgeedge with one Cd(1)O4 trigonal pyramid. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Cs(2), one K(1), two equivalent K(2), one Cd(2), and one Cd(3) atom. In the second O site, O(2) is bonded to one Cs(1), one Cs(2), two equivalent K(2), one Cd(1), and one Cd(3) atom to form distorted OCs2K2Cd2 pentagonal pyramids that share edges with two equivalent O(5)CsK2Cd3 octahedra and  an edgeedge with one O(2)Cs2K2Cd2 pentagonal pyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Cs(2), two equivalent K(1), one Cd(3), and two equivalent Cd(1) atoms. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Cs(2), two equivalent Cs(1), one K(1), one Cd(1), and one Cd(2) atom. In the fifth O site, O(5) is bonded to one Cs(2), one K(1), one K(2), one Cd(3), and two equivalent Cd(2) atoms to form distorted OCsK2Cd3 octahedra that share  an edgeedge with one O(5)CsK2Cd3 octahedra and edges with two equivalent O(2)Cs2K2Cd2 pentagonal pyramids.
Cs2K2Cd3O5 crystallizes in the triclinic P-1 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 3-coordinate geometry to one O(2) and two equivalent O(4) atoms. The Cs(1)-O(2) bond length is 3.06 Å. There is one shorter (2.92 Å) and one longer (3.00 Å) Cs(1)-O(4) bond length. In the second Cs site, Cs(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Cs(2)-O(1) bond length is 3.27 Å. The Cs(2)-O(2) bond length is 3.15 Å. The Cs(2)-O(3) bond length is 3.48 Å. The Cs(2)-O(4) bond length is 3.17 Å. The Cs(2)-O(5) bond length is 2.84 Å. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), and two equivalent O(3) atoms. The K(1)-O(1) bond length is 3.13 Å. The K(1)-O(4) bond length is 2.83 Å. The K(1)-O(5) bond length is 2.84 Å. There is one shorter (2.78 Å) and one longer (2.79 Å) K(1)-O(3) bond length. In the second K site, K(2) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form distorted KO5 trigonal bipyramids that share  a cornercorner with one Cd(3)O4 tetrahedra, corners with two equivalent Cd(2)O4 tetrahedra, corners with two equivalent Cd(1)O4 trigonal pyramids,  an edgeedge with one Cd(2)O4 tetrahedra, edges with two equivalent Cd(3)O4 tetrahedra, and edges with two equivalent K(2)O5 trigonal bipyramids. The K(2)-O(5) bond length is 2.81 Å. There is one shorter (2.73 Å) and one longer (2.74 Å) K(2)-O(1) bond length. There is one shorter (2.68 Å) and one longer (2.97 Å) K(2)-O(2) bond length. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form distorted CdO4 trigonal pyramids that share  a cornercorner with one Cd(2)O4 tetrahedra,  a cornercorner with one Cd(3)O4 tetrahedra, corners with two equivalent K(2)O5 trigonal bipyramids,  an edgeedge with one Cd(3)O4 tetrahedra, and  an edgeedge with one Cd(1)O4 trigonal pyramid. The Cd(1)-O(2) bond length is 2.23 Å. The Cd(1)-O(4) bond length is 2.22 Å. There is one shorter (2.22 Å) and one longer (2.48 Å) Cd(1)-O(3) bond length. In the second Cd site, Cd(2) is bonded to one O(1), one O(4), and two equivalent O(5) atoms to form distorted CdO4 tetrahedra that share corners with three equivalent Cd(3)O4 tetrahedra, corners with two equivalent K(2)O5 trigonal bipyramids,  a cornercorner with one Cd(1)O4 trigonal pyramid,  an edgeedge with one Cd(2)O4 tetrahedra, and  an edgeedge with one K(2)O5 trigonal bipyramid. The Cd(2)-O(1) bond length is 2.19 Å. The Cd(2)-O(4) bond length is 2.24 Å. There is one shorter (2.22 Å) and one longer (2.41 Å) Cd(2)-O(5) bond length. In the third Cd site, Cd(3) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form CdO4 tetrahedra that share corners with three equivalent Cd(2)O4 tetrahedra,  a cornercorner with one K(2)O5 trigonal bipyramid,  a cornercorner with one Cd(1)O4 trigonal pyramid, edges with two equivalent K(2)O5 trigonal bipyramids, and  an edgeedge with one Cd(1)O4 trigonal pyramid. The Cd(3)-O(1) bond length is 2.24 Å. The Cd(3)-O(2) bond length is 2.32 Å. The Cd(3)-O(3) bond length is 2.25 Å. The Cd(3)-O(5) bond length is 2.26 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Cs(2), one K(1), two equivalent K(2), one Cd(2), and one Cd(3) atom. In the second O site, O(2) is bonded to one Cs(1), one Cs(2), two equivalent K(2), one Cd(1), and one Cd(3) atom to form distorted OCs2K2Cd2 pentagonal pyramids that share edges with two equivalent O(5)CsK2Cd3 octahedra and  an edgeedge with one O(2)Cs2K2Cd2 pentagonal pyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Cs(2), two equivalent K(1), one Cd(3), and two equivalent Cd(1) atoms. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Cs(2), two equivalent Cs(1), one K(1), one Cd(1), and one Cd(2) atom. In the fifth O site, O(5) is bonded to one Cs(2), one K(1), one K(2), one Cd(3), and two equivalent Cd(2) atoms to form distorted OCsK2Cd3 octahedra that share  an edgeedge with one O(5)CsK2Cd3 octahedra and edges with two equivalent O(2)Cs2K2Cd2 pentagonal pyramids.