Guanidine (GND)

Guanidine is the compound with the formula HNC(NH2)2. It is a colourless solid that dissolves in polar solvents. It is a strong base that is used in the production of plastics and explosives. It is found in urine as a normal product of protein metabolism. Guanidine is the functional group on the side chain of arginine. Guanidine can be thought of as a nitrogenous analogue of carbonic acid functional group. That is, the C=O group in carbonic acid is replaced by a C=NH group, and each OH is replaced by a NH2 group. Guanidine is protonated in physiological conditions. This conjugate acid is called the guanidinium cation, [CH6N3]+. The guanidinium cation has a charge of +1. It is a highly stable cation in aqueous solution due to the efficient resonance stabilization of the charge and efficient solvation by water molecules. Guanidine can be obtained from natural sources, being formed by the oxidation of guanine.