Naphthalene is a polycyclic aromatic hydrocarbon composed of two fused benzene rings, resulting in a molecular formula of C$_{10}$H$_8$. This compound is a key example of polycyclic aromatic hydrocarbons due to its stability and characteristic properties, such as its ability to undergo electrophilic substitution reactions. Naphthalene's aromatic nature also connects it to Hückel's rule, which dictates the stability of cyclic compounds with a certain number of pi electrons.
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