Jacobus Henricus van 't Hoff

Jacobus Henricus van 't Hoff Jr. was a Dutch physical chemist born 30 August 1852. In 1874 he published a pamphlet proposing that carbon atoms arrange themselves in three-dimensional tetrahedrons, not flat planes - a leap that founded stereochemistry and explained why some molecules are mirror images of others. A year later he predicted the structures of allenes and cumulenes and described their axial chirality. His theoretical work on chemical affinity, equilibrium, kinetics, and thermodynamics helped create physical chemistry as a distinct field. He died 1 March 1911, leaving a framework that turned chemistry from craft into rigorous science.