Crystal structure of the monoclinic phase (phase IV) of bis-(tetra-methyl-ammonium) tetra-chlorido-cuprate(II).

The crystal structure of the low-temperature monoclinic phase of the title compound, [(CH3)4N]2[CuCl4], was determined at 120 K. The structure of the room-temperature phase has been determined in the ortho-rhom-bic space group Pmcm [Morosin & Lingafelter (1961 ▸). J. Phys. Chem. 50-51; Clay et al. (1975 ▸). Acta Cryst. B31 289-290]. The asymmetric unit consists of one discrete tetra-chlorido-cuprate anion with a distorted tetra-hedral geometry and two tetra-methyl-ammonium cations. In the crystal, the cations and the anions are linked via weak C-H⋯Cl hydrogen bonds.