April 7, 1894—February 9, 1987


LOUIS P. HAMMETT was one of the founders of physical-organic chemistry, and a major contributor to it. Together with Arthur Lapworth and Christopher Ingold he created a new branch of chemistry, a new discipline. The ideas and principles of physical-organic chemistry changed the world's teaching and practice of chemistry and, in particular, changed the way synthetic organic chemistry is performed, with enormous practical consequences.

All important practitioners of synthesis today make extensive use of mechanisms of reactions and the stereochemistry of reactions. The understanding of mechanism and stereochemistry was strongly advanced not only by Hammett's research but especially by his famous textbook Physical-Organic Chemistry.1 The concepts on which chemists today depend include an acidity function that Hammett invented and a famous equation named for him that allows a quantitative understanding of chemical reactivity.


Louis Hammett was born in 1894 while his parents were visiting Wilmington, Delaware, so that this most quintessential New Englander managed to begin his life south of the Mason-Dixon line. He grew up, however, in Portland, Maine.

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