K3YCl6 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(3), one Cl(5), one Cl(6), two equivalent Cl(2), and two equivalent Cl(4) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Cl(2), one Cl(3), one Cl(5), two equivalent Cl(1), and two equivalent Cl(6) atoms. In the third K site, K(3) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(2), one Cl(5), one Cl(6), two equivalent Cl(3), and two equivalent Cl(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in an octahedral geometry to two equivalent Cl(2), two equivalent Cl(3), and two equivalent Cl(4) atoms. In the second Y site, Y(2) is bonded in an octahedral geometry to two equivalent Cl(1), two equivalent Cl(5), and two equivalent Cl(6) atoms. There are six inequivalent Cl sites. In the first Cl site, Cl(5) is bonded to one K(1), one K(2), one K(3), and one Y(2) atom to form distorted ClK3Y trigonal pyramids that share corners with four equivalent Cl(6)K4Y square pyramids, corners with two equivalent Cl(3)K4Y trigonal bipyramids, corners with two equivalent Cl(4)K4Y trigonal bipyramids,  a cornercorner with one Cl(5)K3Y trigonal pyramid,  an edgeedge with one Cl(6)K4Y square pyramid,  an edgeedge with one Cl(3)K4Y trigonal bipyramid, and  an edgeedge with one Cl(4)K4Y trigonal bipyramid. In the second Cl site, Cl(6) is bonded to one K(1), one K(3), two equivalent K(2), and one Y(2) atom to form distorted ClK4Y square pyramids that share  a cornercorner with one Cl(6)K4Y square pyramid,  a cornercorner with one Cl(3)K4Y trigonal bipyramid, corners with two equivalent Cl(4)K4Y trigonal bipyramids, corners with four equivalent Cl(5)K3Y trigonal pyramids,  an edgeedge with one Cl(6)K4Y square pyramid,  an edgeedge with one Cl(4)K4Y trigonal bipyramid, edges with two equivalent Cl(3)K4Y trigonal bipyramids, and  an edgeedge with one Cl(5)K3Y trigonal pyramid. In the third Cl site, Cl(1) is bonded in a 5-coordinate geometry to one K(1), one K(3), two equivalent K(2), and one Y(2) atom. In the fourth Cl site, Cl(2) is bonded in a 5-coordinate geometry to one K(2), one K(3), two equivalent K(1), and one Y(1) atom. In the fifth Cl site, Cl(3) is bonded to one K(1), one K(2), two equivalent K(3), and one Y(1) atom to form distorted ClK4Y trigonal bipyramids that share  a cornercorner with one Cl(6)K4Y square pyramid, corners with two equivalent Cl(4)K4Y trigonal bipyramids, corners with three equivalent Cl(3)K4Y trigonal bipyramids, corners with two equivalent Cl(5)K3Y trigonal pyramids, edges with two equivalent Cl(6)K4Y square pyramids, edges with three equivalent Cl(4)K4Y trigonal bipyramids, and  an edgeedge with one Cl(5)K3Y trigonal pyramid. In the sixth Cl site, Cl(4) is bonded to two equivalent K(1), two equivalent K(3), and one Y(1) atom to form distorted ClK4Y trigonal bipyramids that share corners with two equivalent Cl(6)K4Y square pyramids,  a cornercorner with one Cl(4)K4Y trigonal bipyramid, corners with two equivalent Cl(3)K4Y trigonal bipyramids, corners with two equivalent Cl(5)K3Y trigonal pyramids,  an edgeedge with one Cl(6)K4Y square pyramid, edges with two equivalent Cl(4)K4Y trigonal bipyramids, edges with three equivalent Cl(3)K4Y trigonal bipyramids, and  an edgeedge with one Cl(5)K3Y trigonal pyramid.
K3YCl6 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(3), one Cl(5), one Cl(6), two equivalent Cl(2), and two equivalent Cl(4) atoms. The K(1)-Cl(1) bond length is 3.25 Å. The K(1)-Cl(3) bond length is 3.09 Å. The K(1)-Cl(5) bond length is 3.00 Å. The K(1)-Cl(6) bond length is 3.59 Å. There is one shorter (3.35 Å) and one longer (3.62 Å) K(1)-Cl(2) bond length. There is one shorter (3.25 Å) and one longer (3.26 Å) K(1)-Cl(4) bond length. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Cl(2), one Cl(3), one Cl(5), two equivalent Cl(1), and two equivalent Cl(6) atoms. The K(2)-Cl(2) bond length is 3.67 Å. The K(2)-Cl(3) bond length is 3.35 Å. The K(2)-Cl(5) bond length is 3.16 Å. There is one shorter (3.27 Å) and one longer (3.63 Å) K(2)-Cl(1) bond length. There is one shorter (3.17 Å) and one longer (3.46 Å) K(2)-Cl(6) bond length. In the third K site, K(3) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(2), one Cl(5), one Cl(6), two equivalent Cl(3), and two equivalent Cl(4) atoms. The K(3)-Cl(1) bond length is 3.41 Å. The K(3)-Cl(2) bond length is 3.14 Å. The K(3)-Cl(5) bond length is 3.15 Å. The K(3)-Cl(6) bond length is 3.27 Å. There is one shorter (3.30 Å) and one longer (3.59 Å) K(3)-Cl(3) bond length. There is one shorter (3.15 Å) and one longer (3.21 Å) K(3)-Cl(4) bond length. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in an octahedral geometry to two equivalent Cl(2), two equivalent Cl(3), and two equivalent Cl(4) atoms. Both Y(1)-Cl(2) bond lengths are 2.63 Å. Both Y(1)-Cl(3) bond lengths are 2.64 Å. Both Y(1)-Cl(4) bond lengths are 2.66 Å. In the second Y site, Y(2) is bonded in an octahedral geometry to two equivalent Cl(1), two equivalent Cl(5), and two equivalent Cl(6) atoms. Both Y(2)-Cl(1) bond lengths are 2.60 Å. Both Y(2)-Cl(5) bond lengths are 2.62 Å. Both Y(2)-Cl(6) bond lengths are 2.68 Å. There are six inequivalent Cl sites. In the first Cl site, Cl(5) is bonded to one K(1), one K(2), one K(3), and one Y(2) atom to form distorted ClK3Y trigonal pyramids that share corners with four equivalent Cl(6)K4Y square pyramids, corners with two equivalent Cl(3)K4Y trigonal bipyramids, corners with two equivalent Cl(4)K4Y trigonal bipyramids,  a cornercorner with one Cl(5)K3Y trigonal pyramid,  an edgeedge with one Cl(6)K4Y square pyramid,  an edgeedge with one Cl(3)K4Y trigonal bipyramid, and  an edgeedge with one Cl(4)K4Y trigonal bipyramid. In the second Cl site, Cl(6) is bonded to one K(1), one K(3), two equivalent K(2), and one Y(2) atom to form distorted ClK4Y square pyramids that share  a cornercorner with one Cl(6)K4Y square pyramid,  a cornercorner with one Cl(3)K4Y trigonal bipyramid, corners with two equivalent Cl(4)K4Y trigonal bipyramids, corners with four equivalent Cl(5)K3Y trigonal pyramids,  an edgeedge with one Cl(6)K4Y square pyramid,  an edgeedge with one Cl(4)K4Y trigonal bipyramid, edges with two equivalent Cl(3)K4Y trigonal bipyramids, and  an edgeedge with one Cl(5)K3Y trigonal pyramid. In the third Cl site, Cl(1) is bonded in a 5-coordinate geometry to one K(1), one K(3), two equivalent K(2), and one Y(2) atom. In the fourth Cl site, Cl(2) is bonded in a 5-coordinate geometry to one K(2), one K(3), two equivalent K(1), and one Y(1) atom. In the fifth Cl site, Cl(3) is bonded to one K(1), one K(2), two equivalent K(3), and one Y(1) atom to form distorted ClK4Y trigonal bipyramids that share  a cornercorner with one Cl(6)K4Y square pyramid, corners with two equivalent Cl(4)K4Y trigonal bipyramids, corners with three equivalent Cl(3)K4Y trigonal bipyramids, corners with two equivalent Cl(5)K3Y trigonal pyramids, edges with two equivalent Cl(6)K4Y square pyramids, edges with three equivalent Cl(4)K4Y trigonal bipyramids, and  an edgeedge with one Cl(5)K3Y trigonal pyramid. In the sixth Cl site, Cl(4) is bonded to two equivalent K(1), two equivalent K(3), and one Y(1) atom to form distorted ClK4Y trigonal bipyramids that share corners with two equivalent Cl(6)K4Y square pyramids,  a cornercorner with one Cl(4)K4Y trigonal bipyramid, corners with two equivalent Cl(3)K4Y trigonal bipyramids, corners with two equivalent Cl(5)K3Y trigonal pyramids,  an edgeedge with one Cl(6)K4Y square pyramid, edges with two equivalent Cl(4)K4Y trigonal bipyramids, edges with three equivalent Cl(3)K4Y trigonal bipyramids, and  an edgeedge with one Cl(5)K3Y trigonal pyramid.