Odd Hassel

Odd Hassel (1897-1981), Norwegian physical chemist and Nobel laureate. Hassel's innovative research in understanding the three-dimensional structure of molecules demonstrated the importance of these structures to all branches of chemistry. His work garnered him the 1969 Nobel Prize in chemistry (which he shared with Derek H. R. Barton), becoming the first Norwegian scientist to receive this award for work done primarily in Norway.

Hassel was born in Christiania (now Oslo), Norway. While a student at Oslo University, he became interested in kinetics, the study of the movement of molecules. He pursued this interest at the Kaiser Wilhelm Institute in Berlin, Germany, where he studied the crystal structure of various inorganic substances. In 1924 Hassel received his Ph.D. degree from the University of Berlin and a year later returned to Oslo University, where he worked and taught for the remainder of his career.

Fascinated by molecular structures, Hassel experimented with various techniques to study them. In the 1930s and 1940s he used electron diffraction (photographic patterns created when a beam of electrons disperses through a gas) to analyze molecules. Cyclohexane (C₆H₁₂), a compound found in many natural and synthetic substances, commanded most of his attention. Although they knew that the carbon atoms in cyclohexane are arranged in a ring structure, chemists could not discover the exact spatial orientation of each atom. Through experimentation, Hassel determined the molecular arrangement of cyclohexane. His work on molecular shape (called conformation) enabled scientists to better understand the behavior of all molecules containing rings of atoms. It also helped chemists understand how a molecule's shape can determine its physical and chemical properties.

During World War II (1939-1945), Hassel was unable to publish his work outside of Norway and, for a time, he did not work at all due to the German occupation of his country. He also was briefly imprisoned but after the war resumed his research on cyclohexane and its related compounds.