Compounds of the composition CuX(2)(NH3)(2)(H2O) (X = heptanoate, octaneate, nonanoate, decanoate or dodecanoate) were prepared, analysed and characterized by vibrational and electron paramagnetic resonance (EPR) spectroscopy and by magnetic susceptibility measurements. The crystal and molecular structure of diammine-aquabis(decanoato)copper(II) was determined by X-ray diffraction. The structure consists of mononuclear units with (4+2) coordination around central copper. Copyright (C) 1996 Elsevier Science Ltd