It can exist for instance in complex natural or synthetic organic molecules.
The fat we eat exists in relatively huge molecules inside food.
It did not say where the electrons were in molecules.
Space seems to be rich in basic organic molecules.
High values of resonance energy are found in aromatic molecules.
The same problem arises for the cohesive forces in molecules.
The presence of the functional group is generally easily established, at least in small molecules.
For example in linear molecules each energy level is split into J+1 components.
Single bonds are also seen in molecules made up of more than two atoms.
A similar thing is true for electrons in atoms and molecules.