Rb3ErCl6 crystallizes in the monoclinic C2/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(3), two equivalent Cl(2), two equivalent Cl(4), and two equivalent Cl(5) atoms. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one Cl(2), one Cl(3), one Cl(4), one Cl(5), two equivalent Cl(1), and two equivalent Cl(6) atoms. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(2), one Cl(4), one Cl(5), two equivalent Cl(3), and two equivalent Cl(6) atoms. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in an octahedral geometry to two equivalent Cl(2), two equivalent Cl(4), and two equivalent Cl(5) atoms. In the second Er site, Er(2) is bonded in an octahedral geometry to two equivalent Cl(1), two equivalent Cl(3), and two equivalent Cl(6) atoms. There are six inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(3), two equivalent Rb(2), and one Er(2) atom. In the second Cl site, Cl(2) is bonded in a 5-coordinate geometry to one Rb(2), one Rb(3), two equivalent Rb(1), and one Er(1) atom. In the third Cl site, Cl(3) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), and one Er(2) atom. In the fourth Cl site, Cl(4) is bonded to one Rb(2), one Rb(3), two equivalent Rb(1), and one Er(1) atom to form distorted face-sharing ClRb4Er square pyramids. In the fifth Cl site, Cl(5) is bonded in a 5-coordinate geometry to one Rb(2), one Rb(3), two equivalent Rb(1), and one Er(1) atom. In the sixth Cl site, Cl(6) is bonded in a 5-coordinate geometry to two equivalent Rb(2), two equivalent Rb(3), and one Er(2) atom.
Rb3ErCl6 crystallizes in the monoclinic C2/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(3), two equivalent Cl(2), two equivalent Cl(4), and two equivalent Cl(5) atoms. The Rb(1)-Cl(1) bond length is 3.55 Å. The Rb(1)-Cl(3) bond length is 3.71 Å. There is one shorter (3.45 Å) and one longer (3.79 Å) Rb(1)-Cl(2) bond length. There is one shorter (3.49 Å) and one longer (3.53 Å) Rb(1)-Cl(4) bond length. There is one shorter (3.48 Å) and one longer (3.76 Å) Rb(1)-Cl(5) bond length. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one Cl(2), one Cl(3), one Cl(4), one Cl(5), two equivalent Cl(1), and two equivalent Cl(6) atoms. The Rb(2)-Cl(2) bond length is 3.21 Å. The Rb(2)-Cl(3) bond length is 3.22 Å. The Rb(2)-Cl(4) bond length is 3.47 Å. The Rb(2)-Cl(5) bond length is 3.39 Å. There is one shorter (3.52 Å) and one longer (3.60 Å) Rb(2)-Cl(1) bond length. There is one shorter (3.37 Å) and one longer (3.40 Å) Rb(2)-Cl(6) bond length. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to one Cl(1), one Cl(2), one Cl(4), one Cl(5), two equivalent Cl(3), and two equivalent Cl(6) atoms. The Rb(3)-Cl(1) bond length is 3.24 Å. The Rb(3)-Cl(2) bond length is 3.50 Å. The Rb(3)-Cl(4) bond length is 3.25 Å. The Rb(3)-Cl(5) bond length is 3.43 Å. There is one shorter (3.44 Å) and one longer (3.65 Å) Rb(3)-Cl(3) bond length. There is one shorter (3.26 Å) and one longer (3.29 Å) Rb(3)-Cl(6) 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(2), two equivalent Cl(4), and two equivalent Cl(5) atoms. Both Er(1)-Cl(2) bond lengths are 2.61 Å. Both Er(1)-Cl(4) bond lengths are 2.62 Å. Both Er(1)-Cl(5) bond lengths are 2.58 Å. In the second Er site, Er(2) is bonded in an octahedral geometry to two equivalent Cl(1), two equivalent Cl(3), and two equivalent Cl(6) atoms. Both Er(2)-Cl(1) bond lengths are 2.62 Å. Both Er(2)-Cl(3) bond lengths are 2.60 Å. Both Er(2)-Cl(6) bond lengths are 2.62 Å. There are six inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(3), two equivalent Rb(2), and one Er(2) atom. In the second Cl site, Cl(2) is bonded in a 5-coordinate geometry to one Rb(2), one Rb(3), two equivalent Rb(1), and one Er(1) atom. In the third Cl site, Cl(3) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), and one Er(2) atom. In the fourth Cl site, Cl(4) is bonded to one Rb(2), one Rb(3), two equivalent Rb(1), and one Er(1) atom to form distorted face-sharing ClRb4Er square pyramids. In the fifth Cl site, Cl(5) is bonded in a 5-coordinate geometry to one Rb(2), one Rb(3), two equivalent Rb(1), and one Er(1) atom. In the sixth Cl site, Cl(6) is bonded in a 5-coordinate geometry to two equivalent Rb(2), two equivalent Rb(3), and one Er(2) atom.