Pauling, Linus Carl (1901-1994)

US theoretical chemist and biologist whose ideas on chemical bonding are fundamental to modern theories of molecular structure. He also investigated the properties and uses of vitamin C as related to human health. He won the Nobel Prize for Chemistry 1954 and the Nobel Peace Prize 1962, having campaigned for a nuclear test-ban treaty. Pauling was born in Portland, Oregon, and studied at Oregon State Agricultural College, getting his PhD from the California Institute of Technology. In Europe 1925-27, he met the chief atomic scientists of the day. He became professor at Caltech 1931, and was director of the Gates and Crellin Laboratories 1936-58 and of the Linus Pauling Institute of Science and Medicine in Menlo Park, California 1973-75. Pauling's work on the nature of the chemical bond included much new information about interatomic distances. Applying his knowledge of molecular structure to proteins in blood, he discovered that many proteins have structures held together with hydrogen bonds, giving them helical shapes. He was a pioneer in the application of quantum mechanical principles to the structures of molecules, relating them to interatomic distances and bond angles by X-ray and electron diffraction, magnetic effects, and thermochemical techniques. In 1928, Pauling introduced the concept of hybridization of bonds. This provided a clear basic insight into the framework structure of all carbon compounds, that is, of the whole of organic chemistry. He also studied electronegativity of atoms and polarization (movement of electrons) in chemical bonds. Electronegativity values can be used to show why certain substances, such as hydrochloric acid, are acid, whereas others, such as sodium hydroxide, are alkaline. Much of this work was consolidated in his book The Nature of the Chemical Bond 1939. In his researches on blood in the 1940s, Pauling investigated immunology and sickle-cell anaemia. Later work confirmed his conviction that the disease is genetic and that normal haemoglobin and the haemoglobin in sickle cells differ in electrical charge. Pauling's work provided a powerful impetus to Crick and Watson in their search for the structure of DNA. Pauling was coauthor of Introduction to Quantum Mechanics 1935; he published two textbooks, General Chemistry 1948 and College Chemistry 1950. During the 1950s he became politically active, his especial concern being the long-term genetic damage resulting from atmospheric nuclear bomb tests. In this, he conflicted with the US establishment and with several of his science colleagues. He was denounced as a pacifist, and a communist, his passport was withdrawn 1952-54, and he was obliged to appear before the US Senate Internal Security Committee. One item in his sustained wide-ranging campaign was his book No More War! 1958. He presented to the UN a petition signed by 11,021 scientists from 49 countries urging an end to nuclear weapons testing, and during the 1960s spent several years on a study of the problems of war and peace at the Center for the Study of Democratic Institutions in Santa Barbara, California.