Sunday, 28 May 2017

Molecular beading

I stumbled across a paper in the Journal of Chemical Education on molecular modelling of fullerenes using beads and I had to give it a go. After getting some beads and nylon thread the fullerenes came together quite quickly.

One thing to note is that the beads do not represent the atoms but the carbon-carbon bonds and where three beads meet up there is an atom in the chemical model. It is better to use long beads to get an accurate molecular model as bonds are usually represented by long rods. Below are the models shown in the paper using longer beads with the pentagons being coloured yellow for clarity.

I also constructed a C60 fullerene from the longer beads however the structure was not very rigid and tended to collapse. This shows the importance of the pi bonds that allow the structure to be rigid by acting to flatten the sp2 hybridised carbons.

This would probably be a good exercise for high school students and there are a great set of instructions in the supplementary information of the paper. However, a good understanding of the arrangement of the pentagons and hexagons is crucial to be able to construct the fullerene out of beads and I would recommend building the C60 fullerene in Avogadro a computer program first and then moving onto the beads.