[ə·sed′am·ə‚dēn hī·drə′klȯ‚rīd] (organic chemistry) C2H6N2·HCl Deliquescent crystals that are long prisms with a melting point reported as either 174°C or 164-166°C; soluble in water and alcohol; used in the synthesis of imidazoles, pyrimidines, and triazines.