The SN2 Reaction

The following animation shows the reaction between methylthiolate and (S)-2-bromobutane:

CH3S(-) + CH3CHBrCH2CH3 ___> CH3SCH(CH3)CH2CH3 + Br(-).
The sodium cation that accompanies the anions is not shown so as to keep the diagram simple.

Push button to view ball&stick model 
Push button to view spacefilling model 
Pause motion 

This animation may be manipulated at any time by click-dragging the image.