KCdGeAs2 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one As(1), one As(4), two equivalent As(2), and two equivalent As(3) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one As(2), two equivalent As(1), two equivalent As(3), and two equivalent As(4) atoms. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 4-coordinate geometry to one Ge(1), one As(2), one As(3), and two equivalent As(1) atoms. In the second Cd site, Cd(2) is bonded in a distorted trigonal non-coplanar geometry to one As(1), one As(3), and one As(4) atom. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 5-coordinate geometry to one Cd(1), one Ge(1), one As(1), one As(2), and one As(4) atom. In the second Ge site, Ge(2) is bonded to one Ge(2), one As(2), one As(3), and one As(4) atom to form distorted GeGeAs3 tetrahedra that share  a cornercorner with one As(2)K3CdGe2 octahedra and  a cornercorner with one As(4)K3CdGe2 octahedra. The corner-sharing octahedral tilt angles are 79°. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 7-coordinate geometry to one K(1), two equivalent K(2), one Cd(2), two equivalent Cd(1), and one Ge(1) atom. In the second As site, As(2) is bonded to one K(2), two equivalent K(1), one Cd(1), one Ge(1), and one Ge(2) atom to form distorted AsK3CdGe2 octahedra that share corners with two equivalent As(4)K3CdGe2 octahedra,  a cornercorner with one Ge(2)GeAs3 tetrahedra,  an edgeedge with one As(2)K3CdGe2 octahedra, and edges with two equivalent As(4)K3CdGe2 octahedra. The corner-sharing octahedral tilt angles range from 68-97°. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent K(1), two equivalent K(2), one Cd(1), one Cd(2), and one Ge(2) atom. In the fourth As site, As(4) is bonded to one K(1), two equivalent K(2), one Cd(2), one Ge(1), and one Ge(2) atom to form AsK3CdGe2 octahedra that share corners with two equivalent As(2)K3CdGe2 octahedra,  a cornercorner with one Ge(2)GeAs3 tetrahedra,  an edgeedge with one As(4)K3CdGe2 octahedra, and edges with two equivalent As(2)K3CdGe2 octahedra. The corner-sharing octahedral tilt angles range from 68-97°.
KCdGeAs2 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one As(1), one As(4), two equivalent As(2), and two equivalent As(3) atoms. The K(1)-As(1) bond length is 3.79 Å. The K(1)-As(4) bond length is 3.61 Å. There is one shorter (3.38 Å) and one longer (3.43 Å) K(1)-As(2) bond length. There is one shorter (3.54 Å) and one longer (3.68 Å) K(1)-As(3) bond length. In the second K site, K(2) is bonded in a 7-coordinate geometry to one As(2), two equivalent As(1), two equivalent As(3), and two equivalent As(4) atoms. The K(2)-As(2) bond length is 3.47 Å. There is one shorter (3.53 Å) and one longer (3.70 Å) K(2)-As(1) bond length. There is one shorter (3.50 Å) and one longer (3.78 Å) K(2)-As(3) bond length. There is one shorter (3.38 Å) and one longer (3.49 Å) K(2)-As(4) bond length. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 4-coordinate geometry to one Ge(1), one As(2), one As(3), and two equivalent As(1) atoms. The Cd(1)-Ge(1) bond length is 3.14 Å. The Cd(1)-As(2) bond length is 2.77 Å. The Cd(1)-As(3) bond length is 2.70 Å. There is one shorter (2.77 Å) and one longer (2.94 Å) Cd(1)-As(1) bond length. In the second Cd site, Cd(2) is bonded in a distorted trigonal non-coplanar geometry to one As(1), one As(3), and one As(4) atom. The Cd(2)-As(1) bond length is 2.75 Å. The Cd(2)-As(3) bond length is 2.68 Å. The Cd(2)-As(4) bond length is 2.73 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 5-coordinate geometry to one Cd(1), one Ge(1), one As(1), one As(2), and one As(4) atom. The Ge(1)-Ge(1) bond length is 2.49 Å. The Ge(1)-As(1) bond length is 2.49 Å. The Ge(1)-As(2) bond length is 2.52 Å. The Ge(1)-As(4) bond length is 2.50 Å. In the second Ge site, Ge(2) is bonded to one Ge(2), one As(2), one As(3), and one As(4) atom to form distorted GeGeAs3 tetrahedra that share  a cornercorner with one As(2)K3CdGe2 octahedra and  a cornercorner with one As(4)K3CdGe2 octahedra. The corner-sharing octahedral tilt angles are 79°. The Ge(2)-Ge(2) bond length is 2.46 Å. The Ge(2)-As(2) bond length is 2.48 Å. The Ge(2)-As(3) bond length is 2.51 Å. The Ge(2)-As(4) bond length is 2.50 Å. There are four inequivalent As sites. In the first As site, As(1) is bonded in a 7-coordinate geometry to one K(1), two equivalent K(2), one Cd(2), two equivalent Cd(1), and one Ge(1) atom. In the second As site, As(2) is bonded to one K(2), two equivalent K(1), one Cd(1), one Ge(1), and one Ge(2) atom to form distorted AsK3CdGe2 octahedra that share corners with two equivalent As(4)K3CdGe2 octahedra,  a cornercorner with one Ge(2)GeAs3 tetrahedra,  an edgeedge with one As(2)K3CdGe2 octahedra, and edges with two equivalent As(4)K3CdGe2 octahedra. The corner-sharing octahedral tilt angles range from 68-97°. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent K(1), two equivalent K(2), one Cd(1), one Cd(2), and one Ge(2) atom. In the fourth As site, As(4) is bonded to one K(1), two equivalent K(2), one Cd(2), one Ge(1), and one Ge(2) atom to form AsK3CdGe2 octahedra that share corners with two equivalent As(2)K3CdGe2 octahedra,  a cornercorner with one Ge(2)GeAs3 tetrahedra,  an edgeedge with one As(4)K3CdGe2 octahedra, and edges with two equivalent As(2)K3CdGe2 octahedra. The corner-sharing octahedral tilt angles range from 68-97°.