in toluene Irradiation (UV/VIS); a soln. of chlorogermane and diimidazolidine irradiating for 20 h at -60°C, cold MeOH adding, digermane ppt. sepg., washing with cold MeOH under Ar, drying in vacuo at room temp.; identified by elem. anal., IR, UV, NMR and mass spectra;