To overcome the diffuculty of representing three-dimensional structures in two dimensions, chemists have invented several different approaches, each valuable to illustrate certain molecular features. In constructing these diagrams, it is usual to use one filled-in wedge, one dashed wedge and two simple lines. Note also that a switch from one diagram to the other can be achieved by switching any two of the groups attached to the chirality centre. Make sure that you see the different stereoisomer represented by each diagram. Observe that the two diagrams can be interchanged by exchanging any two of the groups attached to the chirality centre.
Exercises Try the following exercises .