On the Surprising Kinetic Stability of Carbonic Acid (H2CO3)

A half-life of 0.18 million years for dry H2CO3 at 300 K clearly demonstrates that carbonic acid is not unstable, as is erroneously taught in high school and in many classical textbooks. Thus, H2CO3 possibly exists in outer space. Nevertheless, proton transfer mediated by just two catalytic water molecules leads to a decomposition (scheme shows analogous reaction with one water molecule) which is nearly as quick as that in aqueous solution.