Lewis Structures and Resonance Contributors: Explained

In chemistry, when we look at structures that can represent the same compound, we may either be discussing different compounds or what are known as resonance contributors. Resonance contributors are different Lewis structures that represent the same compound, where the actual molecule is the average of these structures, called a resonance hybrid.

The classic example of resonance contributors is benzene (C6H6). None of its contributing structures exist on their own; instead, the molecule is a hybrid of these structures, showing that all C-C bonds are equivalent. This differs from isomers, which are compounds having the same molecular formula but different structural arrangements, leading to different properties. Structural isomers are a type of isomer where the connectivity of atoms differs.

Since the question is framed in a way that describes two or more contributing structures for a single compound, the correct answer would be that these are neither different compounds nor isomers, but are indeed resonance contributors representing the same compound.