The authors proposed a novel ammonia synthesis method from water vapor and nitrogen gas under atmospheric pressure at lower temperature than the Haber-Bosch process. In this process, water vapor reacts with nitride ions (N3-) to form ammonia and oxide ions in molten salts. By conducting electrolysis, nitride ions are supplied into the melt at the cathode and oxide ions are removed from the melt at the anode. In the present study, ammonia synthesis according to above principle was confirmed to be possible experimentally. (C) 2005 Elsevier Ltd. All rights reserved.