Sparkling news from the "ghost" in a bottle
Does it exist, or is it just a hypothetical intermediate? Everyone thinks they know carbonic acid, but until recently it was not clear whether the molecule only existed in the minds of chemists. The doubts have now finally been dispelled, because scientists have for the first time succeeded in producing carbonic acid and examining its properties. When it comes to basic chemical research, most people probably think of huge, unmanageable formulas and calculations. In fact, well-known substances such as carbonic acid still hold many mysteries. Scientists from the Institute for General, Inorganic and Theoretical Chemistry at the University of Innsbruck recently succeeded in producing pure carbonic acid. In a publication in Science, the Innsbruck researchers describe that carbonic acid can also exist as a gas and be precipitated again as a solid.
We are talking about carbonic acid (H2CO3), not carbon dioxide (CO2), which escapes from our mineral water and mufflers and is a decomposition product of carbonic acid. Carbonic acid is formed, at least according to the theory, when one of its s alts, such as sodium bicarbonate, is brought into contact with an acid. "Until a few years ago, it was unclear whether the molecule H2CO3, i.e. carbonic acid, was actually formed, or whether it was immediately converted into carbon dioxide and water breaks down," explained Andreas Hallbrucker, co-author of the Science publication.
Using a special process, the chemists succeeded in producing and detecting the carbonic acid molecule at temperatures of around minus 70 degrees. Further studies have now shown that the molecule remains stable even at higher temperatures. Using spectroscopic infrared investigations, the Innsbruck scientists detected carbonic acid as a gas and as a solid. "Two of the molecules combine to form so-called dimers, which obviously increases stability," says Hallbrucker.
The Innsbruck studies have caused a stir, not least among astronomers. "Our investigations suggest that real carbonic acid could also exist in space alongside carbon dioxide and water," say the researchers. These results would also explain previously puzzling observations made with infrared space telescopes.