Nothing breaks in science: the truth about “impossible” molecules

Many newspapers, including international ones, report the news that we have obtained molecules deemed “impossible” because they would have broken the Grant law theorized in 1924. In this specific case it concerns a …

Nothing breaks in science: the truth about "impossible" molecules


Many newspapers, including international ones, report the news that we have obtained molecules deemed “impossible” because they would have broken the Grant law theorized in 1924. In this specific case it concerns a study published in Science by a group of researchers from Los Angeles who proved how organic molecules can be obtained (organic, be careful, it does not mean alive, as in the common sense, but made up of carbon atoms, which is the atom at the basis of life) with double bonds between carbon atoms which are found in particular positions of the molecule, and these molecules could be used in the medical field. In the informative passage (because then no one actually goes to read the study), for sensationalism, we read that molecules considered “impossible” have been created, because we really like to think about the impossible becoming possible.

In reality, a way has been found to stabilize molecules that were considered unstable, so if anything, as the molecular biologist Francesco Cacciante also comments, “Grant’s rule has been expanded, nothing is broken in science” (by the way, it is also a excellent popularizer, follow him on Youtube, Instagram and Tik Tok, his channels are called “Hunting for science”). In short, a chemical way has been found to do something that he didn’t know how to do before, which is a great thing, but no one ever thought it was impossible.

But even those who do the research find it convenient to use bombastic terms, because they talk about it more, only then it becomes a wireless telephone and from step to step the words change meaning. I’ll give you an example: Einstein’s relativity does not break Newton’s law of universal gravitation, but builds another model (much more complex) that does not cancel it, but expands it, as well as giving a model of the universe that works for a hundred years. Therefore it would not even be correct to speak of “gravity force” anymore, but of “space-time deformation”. We know that it is not a “force”, but on Earth we can continue to use Newton’s equations, they work the same (if instead we did not apply relativity on the satellites, a GPS would not work, because time, in orbit, times the speed and the lower gravity, it flows differently from that on Earth).

A similar misunderstanding happened with the discovery of the existence of the Higgs boson, also called “the God particle”, and in the media it seemed that they had found something metaphysical. The reality is that physicists called it that simply because they couldn’t find it, Higgs got the Nobel when the field he theorized that gives mass to particles was found, thanks to the CERN particle accelerator.

«This way of reporting scientific news in the Italian media always makes me smile» confirms Cacciante (who despite his young age brought a study to Copenhagen on a new biomarker of widespread inflammation in multiple sclerosis»), to whom I ask for a more detailed comment. specific. «But in my opinion it is serious to spread this idea that the laws of physics are being broken. Usually what happens is that new pieces of knowledge are added to previous theories, or they are expanded. Think of Newton’s law of gravity, with the advent of relativity it was discovered that that law was incomplete, but not wrong, in fact it continues to work very well when you look at a restricted system. In this case we are talking about molecules that break the rules of stereochemistry. For those who don’t know, molecules are not dimensionless entities, but take on very precise geometries in space, often even three-dimensional. These geometries are defined on the basis of how the electrons arrange themselves in the orbitals around the nucleus, and there is a finite number of allowed geometries.

For example, too narrow angles between 3 atoms are often prohibited because they make the molecule unstable. In this study they managed to obtain a molecule that presents precisely one of these “not permitted” geometries. But then have they really broken a physical law? No. And they give the answer themselves when they say that they have indeed obtained this “unpermitted” geometry, but also that after obtaining it they have stabilized the molecule in some way.

It is clear that this is an excellent result because it opens up the possibility of obtaining previously unforeseen molecules. But the result is not that a physical law has been broken. Rather, that we have found a way around it. But that rule continues to exist.”