The Nobel Prize in Chemistry 1962
Presentation Speech by Professor G. Hägg, member of the Nobel Committee for Chemistry of
the Royal Swedish Academy of
Your Majesties, Your Royal Highnesses, Ladies and Gentlemen.
In the year 1869 the Swedish chemist Christian Wilhelm Blomstrand wrote, in his at that time remarkable book
(Chemistry of Today):
"It is the important task of the chemist to reproduce faithfully in his own way the elaborate constructions which we call
chemical compounds, in the erection of which the atoms serve as building stones, and to determine the number and relative
positions of the points of attack at which any atom attaches itself to any other; in short, to determine the distribution of the
atoms in space."
In other words, Blomstrand gives here as his goal the knowledge of how compounds are built up from atoms, i.e. knowledge
of what is nowadays often called their "structure". Moreover, structure determination has been one of the biggest tasks of
chemical research, and has been approached using many different techniques. For several reasons, the structure
determination of carbon compounds, the so-called organic compounds, experienced an initial rapid development. At this stage
the techniques were generally those of pure chemistry. One drew conclusions from the reactions of a compound, one studied
its degradation products, and tried to synthesize it by combining simpler compounds. The structure thus arrived at, however,
was in general rather schematic in character; it showed which atoms were bonded to a given atom, but gave no precise
values for interatomic distances or interbond angles. However, for an up-to-date treatment of the chemical bond and in order
to derive a correlation between structure and properties, these values are needed, and they can only be obtained using the
techniques of physics.
The physical method which, more than any other, has contributed to our present-day knowledge of these mutual dispositions
of the atoms is founded on the phenomenon which occurs when an X-ray beam meets a crystal. This phenomenon, called
diffraction, results in the crystal sending out beams of X-rays in certain directions. These beams are described as reflections.
The directions and intensities of such reflections depend on the type and distribution of the atoms within the crystal, and can