Crystal Structure of (NH4)2CuCl4

The crystal structure of the yellow compound (NH4)2CuCl4 has been determined by x-ray diffraction studies. The compound crystallizes in the orthorhombic space group Cmca with a=15.46 Å, b=7.20 Å, and c=7.20 Å. The structure contains discrete, planar CuCl4= ions with Cu–Cl distances of 2.30 and 2.33 Å. These ions are then bonded together by longer Cu–Cl bonds of 2.79 Å to form infinite two-dimensional sheets. The yellow compounds (CH3NH3)2CuCl4 and (C2H5NH3)2CuCl4 probably have closely related structures.