My textbook says 2-bromobutane is chiral, but it look like it will form superimposition mirror image
For a molecule to be chiral it must have non-superimposable mirror images. Here is a drawing of the two mirror images for 2-bromobutane.
The chiral carbon atom is denoted by an asterisk. In the case of 2-bromobutane there are 4 different substituents attached to it. The molecule is chiral, you can't pick up one of the mirror images and superimpose it on the other.
Note to think about:
- 4 different substituents may make an atom chiral, but the molecule as a whole may still be achiral
For example meso compounds
- some molecules without 4 different substituents attached to an atom may still be chiral .
For example, compounds with axial chirality such as chiral allenes (1,3-dimethylallene), chiral biphenyls, chiral helicenes, etc.