Linus Pauling

Linus Carl Pauling was born on February 28, 1901, in Portland, Oregon, the first child of Herman Pauling, a pharmacist, and Lucy Isabelle Darling Pauling ^[1]. The family moved to the small town of Condon in eastern Oregon during his early childhood before returning to Portland, where Herman died suddenly in 1910. His death left the household in difficult financial circumstances, and Lucy took in boarders while her son worked odd jobs to help pay bills ^[2].

A friend's chemistry set, encountered when Pauling was about thirteen, set the direction of his life. He began running experiments with borrowed and scavenged equipment in a basement laboratory, and he later recalled deciding almost immediately that he would become a chemist ^[2]. Formal schooling mattered less to him than his own reading. He left Washington High School in Portland without a diploma after refusing to take a required civics course, a gap the school filled only decades later when it awarded the degree to a two-time Nobel laureate ^[1].

In 1917 Pauling enrolled at Oregon Agricultural College in Corvallis, now Oregon State University, to study chemical engineering. Money remained tight, and at one point the college hired the undergraduate to teach a quantitative analysis course he had completed only the year before ^[3]. While teaching a chemistry class for home economics students he met Ava Helen Miller, whom he would marry in 1923. He graduated in 1922 and headed south to the California Institute of Technology for doctoral work ^[3].

At Caltech, Pauling worked under Roscoe Dickinson learning X-ray crystallography, the technique of determining the arrangement of atoms in crystals from diffraction patterns. His first published structure, that of the mineral molybdenite, appeared in 1923, and he completed his PhD in 1925 with highest honors ^[3]. A Guggenheim Fellowship then carried him to Europe in 1926 and 1927, where he studied the new quantum mechanics with Arnold Sommerfeld in Munich, Niels Bohr in Copenhagen, and Erwin Schrödinger in Zurich ^[1].

That European apprenticeship proved decisive. Pauling grasped earlier than most chemists that quantum mechanics could explain why atoms bond and why molecules take the shapes they do. Back at Caltech as a faculty member from 1927, he published a stream of papers applying wave mechanics to chemical problems, introducing ideas such as orbital hybridization and resonance to account for the geometry of molecules like methane and benzene ^[4].

He also devised a practical scale of electronegativity, a measure of how strongly an atom in a molecule attracts electrons, which chemists still use in classrooms today ^[4]. In 1932 he became a full professor, and in 1939 he gathered his ideas into The Nature of the Chemical Bond and the Structure of Molecules and Crystals, a book that became one of the most cited scientific works of the twentieth century and trained generations of chemists to think structurally ^[1].

Any list of Linus Pauling achievements begins with the chemical bond, the work honored by the 1954 Nobel Prize in Chemistry, awarded for his research into the nature of the chemical bond and its application to the structure of complex substances ^[5]. But by the late 1930s his attention had already turned to biology. Working with Robert Corey and using precise structural data on amino acids, Pauling proposed in 1951 that protein chains coil into a spiral he called the alpha helix, held together by hydrogen bonds, along with a second arrangement called the beta sheet ^[4]. Both structures were later confirmed and remain foundations of structural biology.

In 1949 Pauling, with Harvey Itano and colleagues, published a paper showing that sickle cell anemia arises from an abnormal hemoglobin molecule. The paper, titled Sickle Cell Anemia, a Molecular Disease, effectively founded the field of molecular medicine by tracing an inherited illness to a defect in a single protein ^[6]. Earlier, in 1940, he and Max Delbrück had argued that biological molecules replicate through complementary structures rather than identical copies, an idea that anticipated how DNA works ^[2].

DNA itself brought his most famous miss. Early in 1953 Pauling proposed a triple helix structure for DNA with the phosphates on the inside, a model that was chemically flawed. Within weeks James Watson and Francis Crick, partly spurred by the fear that Pauling would correct his error, published the double helix ^[2]. Pauling accepted the new model quickly. His second Nobel came from outside the laboratory entirely: the Nobel Peace Prize for 1962, awarded in 1963, recognized his years of campaigning against atmospheric nuclear weapons testing ^[5]. He had drafted and circulated a petition against such tests that gathered signatures from more than 11,000 scientists worldwide and was presented to the United Nations in 1958 ^[7]. The prize announcement came on October 10, 1963, the day the Partial Test Ban Treaty took effect.

Pauling married Ava Helen Miller on June 17, 1923, and the marriage lasted until her death in 1981. They had four children: Linus Jr., Peter, Linda, and Crellin ^[1]. Ava Helen was far more than a supportive spouse. A committed activist for peace, civil liberties, and women's rights, she drew her husband into political engagement after the Second World War, and Pauling repeatedly credited her influence for the work that led to his Peace Prize ^[7].

His politics carried a price during the McCarthy era. The State Department denied Pauling a passport in 1952, judging his travel not in the best interests of the United States, which kept him from a London conference on protein structure where he might have seen crucial X-ray images of DNA ^[2]. The passport was restored in 1954, shortly before he traveled to Stockholm for the chemistry Nobel. In 1960 a Senate subcommittee demanded the names of those who had helped circulate his test ban petition; Pauling refused and risked a contempt citation rather than expose colleagues ^[7].

Among the lesser known Linus Pauling facts is his lifelong interest in Esperanto, the constructed international language, which fit his conviction that scientists should communicate across borders. Colleagues described him as confident to the point of showmanship, a gifted lecturer who enjoyed performing chemistry for audiences and rarely doubted his own conclusions, a trait that served him well in structural chemistry and less well in his final medical crusade ^[3].

Pauling left Caltech in 1963 after friction over his political activism and spent the next decade moving among institutions: the Center for the Study of Democratic Institutions in Santa Barbara, the University of California at San Diego, and Stanford University ^[1]. In 1973 he co-founded a research institute in Menlo Park, later named the Linus Pauling Institute of Science and Medicine, to pursue his ideas about nutrition and health. The institute moved to Oregon State University in 1996, where it continues as the Linus Pauling Institute ^[3].

His late career was dominated by orthomolecular medicine, his term for treating disease by adjusting concentrations of substances normally present in the body. Beginning with the 1970 book Vitamin C and the Common Cold, Pauling argued that large doses of vitamin C could prevent colds and, later, that it could extend the lives of cancer patients ^[8]. Clinical trials at the Mayo Clinic in the late 1970s and early 1980s failed to confirm the cancer claims, and most of the medical establishment rejected his conclusions, though Pauling defended them for the rest of his life and took large daily doses himself ^[8].

He remained productive into his nineties, publishing on subjects from atomic nuclei to quasicrystals. Ava Helen died of stomach cancer in 1981, after which Pauling divided his time between the institute and a ranch on the Big Sur coast. He was diagnosed with prostate cancer in 1991 and died at the ranch near Big Sur, California, on August 19, 1994, at the age of 93 ^[9].

Pauling remains the only person awarded two unshared Nobel Prizes, and in 2000 a poll of scientists conducted for the millennium ranked him among the greatest chemists in history ^[5]. The conceptual tools he built, electronegativity, hybridization, resonance, and the structural rules for crystals that bear his name, are embedded so deeply in chemistry that students absorb them without knowing their source. His protein work opened the road to modern structural biology, and the sickle cell paper gave medicine a molecular vocabulary it has used ever since ^[6].

His papers, along with those of Ava Helen, fill the special collections of the Oregon State University Libraries, which maintain extensive digital archives documenting both the science and the activism ^[3]. Honors accumulated throughout his life and after it: the National Medal of Science in 1975, election to scientific academies on several continents, and a 2008 United States postage stamp in the American Scientists series. Asteroid 4674 Pauling carries his name as well ^[1].

Any balanced Linus Pauling biography must hold two judgments at once. The vitamin C episode showed how a brilliant scientist could cling to a hypothesis against mounting contrary evidence. Yet the same stubbornness had earlier kept him circulating petitions while critics called him a traitor, and the test ban he fought for measurably reduced radioactive fallout worldwide. Few careers demonstrate so clearly that scientific imagination and public conscience can live, sometimes uneasily, in one person ^[7].