Skeletal formulae revisited

It was interesting to read a recent “pet peeve” from Darrel Beach about skeletal organic formulae.1 For many years he has required his students to explicitly show all four bonds from each carbon atom in every organic molecule they drew. As we indicated in our paper,2 this approach is reasonable for very small and uncomplicated molecules (e.g., methane, ethane and their derivatives) and is the style adopted in very old chemistry textbooks, with formulae taking up a lot of space (and taking a lot of time to draw). In first-year courses at the University of Toronto, we used to observe students trying to save time by drawing only carbon atoms and lines coming from them because they did not want to include all the hydrogen atoms.

Because of this, we welcomed the IUPAC Compendium of Chemical Terminology3 to use skeletal formulae for longer chains and rings. All newer textbooks, scientific journals and even Wikipedia4 currently use such representations. Why is this the case? Skeletal formulae take less space, clearly show all functional groups, are quicker to draw and (most importantly) indicate proper bond angles. We strongly recommend that teachers introduce skeletal formulae in high schools so that students are exposed to them and their meaning as early as possible. We require students to use skeletal structures at our university and formally examine their understanding of them.

Literature cited

  1. D.H. Beach, Chem 13 News, 392, 6, 2012.
  2. S. Skonieczny, A.P. Dicks, Chem 13 News, 372, pages 10-12, 2010.
  3. IUPAC Compendium of Chemical Terminology, 2nd edition (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford, 1997. XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins, 2006.
  4. (accessed September 2012).