IB Chemistry home > Syllabus 2016 > Practical Scheme of Work > Modelling organic molecules

It is very useful to be able to represent the three dimensional structure of organic molecules.

This may be done using computerised techniques or physical models,

Physical modelling

MolymodsTM, in which the atoms are all represented by different coloured spheres with an appropriate number of holes to enable bonding from one sphere to another. In the picture below the black spheres represent carbon atoms and the red spheres represent oxygen atoms. The white spheres are hydrogen atoms.

molecular model of a glucose molecule


Computer representations

There are many programs available that can represent molecules on a screen. They can often be animated to show the molecule rotating or even vibrating.

They can also be made to display the molecules in spacefill or ball and stick representation.

Space-filling representations show the atoms with the correct relative covalent radii.

3D-space filling representation of
4-aminobutanoic acid