zinc under an atmosphere of carbon dioxide Gomberg obtained the free radical (2). This compound reacted readily with air, chlorine, bromine and iodine. On the basis of his experimental evidence Gomberg concluded that he had discovered the first instance of a persistent radical and trivalent carbon. This was a controversial conclusion for many years as molecular weight determinations of (2) found a value that was double that of the free radical. Gomberg postulated that some non-tetravalent carbon structure existed in solution because of the observed activity towards oxygen and the halogens. Gomberg and Bachmann later found that treatment of "hexaphenylethane" with magnesium resulted in a Grignard reagent, the first instance of the formation of such a compound from a hydrocarbon. Studies of other triarylmethyl compounds gave results similar to Gomberg's, and it was hypothesized that (2) existed in equilibrium with its dimer hexaphenylethane (5). However this structure was later disproven in favor of the quinoid dimer (3). At the end of his first report of trivalent carbon "On Trivalent Carbon" Gomberg wrote "This work will be continued and I wish to reserve the field for myself." While nineteenth-century chemists respected such claims Gomberg found that the field of chemistry he founded was too rich to reserve for himself. Legacy Upon his death in 1947 Moses Gomberg bequeathed his estate to the chemistry department of the University of Michigan for the creation of student fellowships. In 2000, the centennial of his paper "Triphenylmethyl, a Case of Trivalent Carbon", a symposium was held in his memory and a plaque was installed in the Chemistry Building at the University of Michigan designating a National Historic Chemical Landmark. In 1993, the chemistry department of the University of Michigan instituted the Moses Gomberg Lecture series to provide assistant professors an opportunity to invite distinguished scientists to the chemistry department. Personal life Gomberg never married, living with his sister Sophia in Ann Arbor for his adult life. References External links Chemistry Department at the University of Michigan Link National Academy of Sciences Biographical Memoir 1866 births 1947 deaths American chemists Organic chemists Ukrainian emigrants to the United States Jewish chemists Ukrainian Jews University of Michigan alumni University of Michigan faculty