Pauling , Linus Carl

(1901–1994) American chemist

Pauling, a pharmacist's son, was born at Portland, Oregon, and graduated in chemical engineering from Oregon State Agricultural College in 1922. Having gained his PhD in physical chemistry from the California Institute of Technology in 1925, he spent two years in Europe working under such famed scientists as Arnold Sommerfeld, Niels Bohr, Erwin Schrödinger, and William Henry Bragg. He was appointed associated professor of chemistry at Cal Tech in 1927 and full professor in 1931.

Pauling worked on a variety of problems in chemistry and biology. His original work in chemistry was on chemical bonding and molecular structure. He applied physical methods, such as x-ray diffraction, electron diffraction, and magnetic effects, to determining the structure of molecules. He also made significant contributions to applying quantum mechanics to the bonding in chemical compounds. In this field he introduced the idea of hybrid atomic orbitals to account for the shapes of molecules. Another of his innovations was the idea of resonance hybrid – a molecule having a structure intermediate between two different conventional structures. Pauling also worked on the partial ionic character of chemical bonds, using the concept of negativity. Pauling's ideas on chemical bonding were collected in his influential book The Nature of the Chemical Bond and the Structure of Molecules and Crystals (1939).

From about 1934 he began to work on more complex biochemical compounds. He studied the properties of hemoglobin using magnetic measurements. This work led on to extensive studies of the nature and structure of proteins. With Robert B. Corey, he showed that the amino-acid chain in certain proteins can have a helical structure.

He made a number of original contributions on other biological topics. In 1940, with Max Delbrück, he introduced a theory of antibody–antigen reactions that depended on molecular shapes. In the 1940s he also studied the genetic disease sickle cell anemia. In 1960 he published a theory of anesthesia and memory. He is noted for his originality and intuition in tackling complex problems and his deep understanding of chemistry. In his bookThe Double Helix, describing the race to determine the structure of DNA, James Watson describes the concern caused by the knowledge that Pauling was working on the same problem.

Pauling was awarded the 1954 Nobel Prize for chemistry. By this time, he had been campaigning for some years against the development of nuclear weapons. He had earlier refused to join the Manhattan project, but had overcome his pacifist principles sufficiently to work on conventional weapons: “Hitler had to be stopped,” he noted. By the early 1950s, campaigns against nuclear weapons were being interpreted as ‘un-American’ and Pauling's passport was withdrawn making it impossible to travel to Stockholm for the Nobel ceremonies; his passport was returned at the last moment. Pauling continued with his campaign, publishing a book, No More War (1958), and organizing a petition of scientists against nuclear testing. He was awarded the Nobel Peace Prize in 1962.

Pauling later began to campaign on another issue, namely the therapeutic value of high doses of vitamin C. In 1971, in hisVitamin C and the Common Cold, Pauling claimed that large vitamin C doses, over 10 grams a day, would also reduce the risk of heart disease. Pauling himself took 18 grams of vitamin C daily, a figure 300 times the recommended dose, for the last 27 years of his life. To pursue the matter further Pauling set up in 1973 the Pauling Institute of Science and Medicine in Palo Alto, California.