Notes on quantitative structure‐properties relationships (QSPR) part 2: The role of the number of atoms as a molecular descriptor

A previous analysis performed in our laboratory about the polynomial dependency of the atomic quantum self‐similarity measures on the atomic number, together with recent publications on quantitative structure‐properties relationships (QSPR), based on the number of molecular atoms, published by various authors, have driven us to show here that a simplified form of the fundamental quantum QSPR (QQSPR) equation, permits to theoretically demonstrate the important, but obvious, role of the number of atoms in a molecule, as a possible molecular descriptor. A discussion of the practical use of the number of atoms in QSPR is also given at the end, which also contains a discussion on the role of Ockham's razor in descriptor simplification choices. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009