Laurent, Auguste (ōgüstˈ lōräNˈ) [key], 1808–53, French organic chemist. He devised a systematic nomenclature for organic chemistry. His studies on naphthalene and its chlorination products led him to propose a nucleus theory that foreshadowed modern structural chemistry; he proposed that the structural grouping of atoms within molecules determined how the molecules combined in organic reactions. This theory conflicted with the then current notion that the product of organic reactions depended solely on the electrical charge of the atoms involved. His theory greatly influenced the theory of types proposed by J. B. Dumas and C. F. Gerhardt.