Nobel Prize Recipient. Odd Hassel, a Norwegian physical chemist, received world-wide recognition after being awarded the 1969 Nobel Prize in Chemistry, sharing the honor with Sir Derek H.R. Barton. The two men were awarded the coveted award, according to the Nobel Prize committee, "for their contributions to the development of the concept of conformation and its application in chemistry." At the end of the 1940s, he published pioneering works about different conformations for ring-shaped molecules with six carbon atoms and the study of the three-dimensional geometric structure of molecules. This research initially started in 1925. Born a twin, his twin brother, Leif, became a lawyer. When he was seven years old, his father, a physician, died at age 57, leaving his widowed mother to provide for him along with three brothers and one sister. In 1915, he started studies at the University of Oslo with lessons in mathematics, physics and chemistry as his major, graduating in 1920. After touring France and Italy, he traveled to Germany in the fall of 1922 to study, while working in various laboratories and eventually at the Kaiser Wilhelm Institute in Dahlem, carrying out X-ray crystallographic work. While there, he received a Rockefeller Fellowship. In 1924, he graduated with a Ph.D. from the University of Berlin. Returning to the University of Oslo in 1925, he began as an assistant in the physical chemistry and electrochemistry department, but advancing regularly. In 1934 he was appointed Norway's first professor of physical chemistry, becoming the department chair of the physical chemistry department. In 1934 he published his paper "Crystal Chemistry." During World War II, Norway was invaded by German Nazi forces. In 1943 the entire staff of the university was sent to internment camps. He continued his research until his release in November of 1944. Shortly after that, he published his paper that led to his Nobel Prize. Besides the Nobel Prize, he received from the Norwegian Chemistry Society in 1964 the Guldberg-Waage Medal; received the Fridtjof Nansen Award of Sciences; received honorary doctorate degrees from the University of Stockholm and the University of Copenhagen; and was a member of several professional societies throughout Europe including the Chemical Society of London. He was made a Knight of the Order of St. Olav in 1960. Although he retired in 1964, he continued his research. He never married.