1: phosphorus pentasulfide / dioxane / 2 h / 60 °C 2: tetraethylammonium ethylsulfate / aq. H2SO4 / 14 h / 27 - 30 °C / electrolitic reduction with lead electrodes View Scheme

diphosphorus pentasulfide in 1,4-dioxane T=60°C; 2 h;