Crystal Structure of (18-Crown-6)-bis(tetrahydrofuran)potassium iodide

The title compound, [K(C12H24O6)(C4H8O)2]I, has iodide anions on crystallographic twofold rotation axes and cations in general positions. The coordination of potassium is distorted hexagonal bipyramidal, with an 18-crown-6 ligand as an equatorial belt and two axial tetra­hydro­furan ligands. Distortion is marked, consisting mainly of a significant bending of the axial arrangement [O-K-O = 148.53 (13)°] and a shortening of the two equatorial K-O bonds closest to the axial O atoms. This conformation is unprecedented in the previous reports of this cation, with almost thirty different occurrences in nearly twenty crystal structures.