Functional groups

Functional groups are the parts of a molecule responsible for its reactivity. Different functional groups give rise to different reaction types in organic chemistry.

Functional groups can be a specific arrangement of carbon and hydrogen, e.g. a double bond, or can also include other elements. The most common elements in organic compounds besides carbon and hydrogen are oxygen and nitrogen. Other examples of elements are phosphorus and halogens. You can see the functional groups of salicylic acid in Figure 1.

Figure 1. The functional groups of salicylic acid. Purple = phenol; green = carboxylic acid; blue = phenyl.

You can see an overview of the most common functional groups here.