Joseph Achille Le Bel
Le Bel, Joseph Achille (zhôsĕfˈ äshēlˈ ləbĕl) [key], 1847–1930, French chemist. He was educated at the École polytechnique and carried out much of his research in his own private laboratory. He theorized (1874) that optical activity—the presence of two forms of the same organic molecule, one a mirror image of the other—is due to an asymmetric carbon atom bound to four different groups. For this contribution he is regarded as the cofounder of stereochemistry, with J. H. van't Hoff. His interests also included petrochemistry, cosmology, and biology.