K3ErCl6 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(2), one Cl(3), one Cl(6), two equivalent Cl(4), and two equivalent Cl(5) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Cl(1), one Cl(2), one Cl(3), one Cl(4), one Cl(6), and two equivalent Cl(5) atoms. In the third K site, K(3) is bonded in a 7-coordinate geometry to one Cl(1), one Cl(4), one Cl(6), two equivalent Cl(2), and two equivalent Cl(3) atoms. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in an octahedral geometry to two equivalent Cl(1), two equivalent Cl(2), and two equivalent Cl(3) atoms. In the second Er site, Er(2) is bonded in an octahedral geometry to two equivalent Cl(4), 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 in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Er(2) atom. In the second Cl site, Cl(6) is bonded in a 4-coordinate geometry to one K(1), one K(2), one K(3), and one Er(2) atom. In the third Cl site, Cl(1) is bonded in a distorted see-saw-like geometry to one K(1), one K(2), one K(3), and one Er(1) atom. In the fourth Cl site, Cl(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), two equivalent K(3), and one Er(1) atom. In the fifth Cl site, Cl(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), two equivalent K(3), and one Er(1) atom. In the sixth Cl site, Cl(4) is bonded in a 5-coordinate geometry to one K(2), one K(3), two equivalent K(1), and one Er(2) atom.
K3ErCl6 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(2), one Cl(3), one Cl(6), two equivalent Cl(4), and two equivalent Cl(5) atoms. The K(1)-Cl(1) bond length is 3.09 Å. The K(1)-Cl(2) bond length is 3.17 Å. The K(1)-Cl(3) bond length is 3.59 Å. The K(1)-Cl(6) bond length is 3.11 Å. There is one shorter (3.26 Å) and one longer (3.63 Å) K(1)-Cl(4) bond length. There is one shorter (3.13 Å) and one longer (3.18 Å) K(1)-Cl(5) bond length. In the second K site, K(2) is bonded in a 7-coordinate geometry to one Cl(1), one Cl(2), one Cl(3), one Cl(4), one Cl(6), and two equivalent Cl(5) atoms. The K(2)-Cl(1) bond length is 2.99 Å. The K(2)-Cl(2) bond length is 3.55 Å. The K(2)-Cl(3) bond length is 3.30 Å. The K(2)-Cl(4) bond length is 3.10 Å. The K(2)-Cl(6) bond length is 3.24 Å. There is one shorter (3.22 Å) and one longer (3.40 Å) K(2)-Cl(5) bond length. In the third K site, K(3) is bonded in a 7-coordinate geometry to one Cl(1), one Cl(4), one Cl(6), two equivalent Cl(2), and two equivalent Cl(3) atoms. The K(3)-Cl(1) bond length is 3.18 Å. The K(3)-Cl(4) bond length is 3.43 Å. The K(3)-Cl(6) bond length is 3.38 Å. There is one shorter (3.19 Å) and one longer (3.38 Å) K(3)-Cl(2) bond length. There is one shorter (3.25 Å) and one longer (3.31 Å) K(3)-Cl(3) bond length. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in an octahedral geometry to two equivalent Cl(1), two equivalent Cl(2), and two equivalent Cl(3) atoms. Both Er(1)-Cl(1) bond lengths are 2.58 Å. Both Er(1)-Cl(2) bond lengths are 2.65 Å. Both Er(1)-Cl(3) bond lengths are 2.59 Å. In the second Er site, Er(2) is bonded in an octahedral geometry to two equivalent Cl(4), two equivalent Cl(5), and two equivalent Cl(6) atoms. Both Er(2)-Cl(4) bond lengths are 2.62 Å. Both Er(2)-Cl(5) bond lengths are 2.63 Å. Both Er(2)-Cl(6) bond lengths are 2.60 Å. There are six inequivalent Cl sites. In the first Cl site, Cl(5) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Er(2) atom. In the second Cl site, Cl(6) is bonded in a 4-coordinate geometry to one K(1), one K(2), one K(3), and one Er(2) atom. In the third Cl site, Cl(1) is bonded in a distorted see-saw-like geometry to one K(1), one K(2), one K(3), and one Er(1) atom. In the fourth Cl site, Cl(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), two equivalent K(3), and one Er(1) atom. In the fifth Cl site, Cl(3) is bonded in a 5-coordinate geometry to one K(1), one K(2), two equivalent K(3), and one Er(1) atom. In the sixth Cl site, Cl(4) is bonded in a 5-coordinate geometry to one K(2), one K(3), two equivalent K(1), and one Er(2) atom.