Odd Hassel

Odd Hassel's electron-diffraction studies of cyclohexane demonstrated that the molecule exists primarily in a non-planar chair conformation rather than a flat structure. This experimental finding, made in the 1930s at the University of Oslo, was foundational to the field of conformational analysis.

Hassel shared the 1969 Nobel Prize in Chemistry with Derek Barton for their foundational contributions to conformational analysis. Barton had built on Hassel's experimental work to develop rules predicting how the three-dimensional conformation of molecules influences their chemical reactivity.

Conformational analysis is the study of how the spatial arrangement of atoms in a molecule affects its physical and chemical properties. The field was formalized through the combined work of Hassel and Barton, who showed that molecules like cyclohexane adopt specific non-planar shapes that profoundly influence reactivity.

Odd Hassel spent his entire academic career at the University of Oslo in Norway. Despite the disruption of World War II, during which Norway was occupied by Nazi Germany and Hassel was temporarily arrested, he returned to his position and continued his structural chemistry research.