Application of anhydrous aluminum chloride to the reactions of arylphosphites and sulfur resulted in the formation of unexpected thiophosphates. These reactions may be written by the following equations. (RO)PCl_2+S AlCl_3→(RO)P(S)Cl_2……(1) 2(RO)PCl_2+2S AlCl_3→(RO)_2P(S)Cl+PSCl_3……(2) 3(RO)PCl_2+3S AlCl_3→(RO)_3P(S)+2PSCl_3……(3) (RO)_2PCl+S AlCl_3→(RO)_2P(S)Cl……(4) 3(RO)_2PCl+3S AlCl_3→2(RO)_3P(S)+PSCl_3……(5) In the case of selenium, the reactions corresponding (3) and (5) governed the whole ones and tertiary seleno-phosphates (ArO)_3P(Se) were formed, but the researches on the formation of a phosphorus seleno chloride was remained for future
