metal-organic compounds
The title compound, [Er(C6H11NO)8][Cr(NCS)6], is a new structure type for [Ln(-caprolactam)8][Cr(NCS)6], where Ln is a lanthanide. There are two independent cations and two independent anions in the asymmetric unit. The Er atom is in a distorted square-antiprismatic environment of eight O atoms of the organic ligands; Er-O bond distances are in the range 2.29-2.44 Å. The coordination environment of the Cr atom is a slightly distorted octahedron; Cr-N bond distances vary from 1.99 to 2.01 Å. The mutual packing of the cations and the anions follows a distorted NaCl motif. One cation has the Er atom on a twofold axis and one of the anions has the Cr atom on a twofold axis.