It is prepared by the direct reaction between liquid ammonia and dry ice (solid carbon dioxide)::2 NH3(l) + CO2(s) → H2NCOONH4==Reactions==Ammonium carbamate undergoes hydration reversibly::NH2CO2NH4 + H2O → (NH4)2CO3It may also revert to carbon dioxide and ammonia as follows::NH2CO2NH4 → 2NH3 + CO2Ammonium carbamate can play a key role in the formation of carbamoyl phosphate, which is necessary for both the urea cycle and the production of pyrimidines.