In December, we published an editorial called “Questioning chemistry” that discussed the definition of chemistry on the back of the recent awarding of the Nobel prize in chemistry for research into the “structure and function of the ribosome”. It was further discussed here on the Sceptical Chymist.
We have since received a comment from Dr. Paolo Ghigna at the University of Pavia giving his views on the apathy of some chemists to the award. These can be found below and may just spark off a little more debate on the subject.
Gavin Armstrong (Associate Editor, Nature Chemistry)
The Editorial in the December 2009 issue of Nature Chemistry remarked on the apathy of the chemical community for the 2009 Nobel prize.
Of course, such a debate would entail the definition of ‘chemistry’, and the editorial defines chemistry as ‘the study of matter and its transformation’. Although it is true, as the editorial says, that “defining research topics is becoming increasingly difficult”, this definition is really too broad to be effective. On one side, elephants are pieces of matter, and during their lives, they go through transformations; on the other side, neutrinos are also pieces of matter that also transform. But no one would doubt the fact that the study of elephants’ life is pertinent to biology, and that studying neutrino oscillations would be the business of physics.
We are then carried back to the question ‘What is chemistry?’. For sure, chemistry is a way of studying matter but we also have to ask how chemists study what kind of matter. To answer this question, as is implicit in the editorial, we need to think about what is the focal point in chemistry classrooms. The large majority of the chemical community would agree that this is the notion of ‘chemical reaction’: chemists are proud of their chemical intuition, that is the ability of being able to predict how a compound would react even in the absence of detailed kinetic and thermodynamic information.
A further step forward can be made simply by looking at the IUPAC definition of a chemical reaction “a process that results in the interconversion of chemical species” Now, a definition of ‘chemical species’ is required. Looking again at IUPAC one finds that a ‘chemical species’ is “an ensemble of chemically identical molecular entities that can explore the same set of molecular energy levels on the time scale of the experiment. The term is applied equally to a set of chemically identical atomic or molecular structural units in a solid array”. Note how, with this definition, questioning about what is pertinent to chemistry does not involve problems of length scale: any crystal of rock salt belongs to a chemical species, is usually much bigger than a ribosome, and is not a molecular species (this is a point chemists tend to forget. For example, CaF2 was named ‘molecule of the week’ on the ACS website).
Probably, one of the reasons for the debate could be that chemists do not recognize a ribosome as a “chemical species”: a ribosome does not fulfill the IUPAC definition. Or, to look at the flip side of the coin, can we apply our chemical intuition to a ribosome?