Octakis(epsilon-caprolactam-kappaO)erbium(III) hexaisothiocyanatochromate(III).

The title compound, [Er(C(6)H(11)NO)(8)][Cr(NCS)(6)], is a new structure type for [Ln(epsilon-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.