Thermolysis of NH4HCO3—A Simple Route to the Formation of Free Carbonic Acid (H2CO3) in the Gas Phase

Abstract

“Carbonic acid cannot exist in the free state.” Now, a surprisingly simple experiment has shown that this statement is wrong. Thermolysis of NH4HCO3 affords, among other products, H2CO3, which is stable as both the neutral molecule and the radical cation. This finding also confirms the results of detailed ab initio and semiempirical calculations, which show that H2CO3 should be stable in the gas phase because the activation energy for its decomposition is large.