Linus Pauling: Well, I began with instruction from Dr. Dickinson, Roscoe Dickinson, to make use
of the technique of the x-ray diffraction of crystals to determine the structure of
crystals. And in the course of some years and later on, of course, with the help of
my students I think I may have determined the structures of a couple of hundred different
crystalline substances. And by the electron diffraction technique, two or three hundred
gas molecules, important molecules that could be put into the gas phase by heating
a liquid or solid. In determining structures we found out how far apart the atoms
are and what the angles are between the bonds. This was important information. And
we could see how one atom could interact with another one, perhaps on the other side
of the molecule.
For example the acetylcholine which affects the brain, which is involved in synaptic
interactions, has two active groups -- one at one end and the other at the other end
of the molecule. We know how far apart they are and know that it is necessary that
these active reagents lie at that distance in order to interact with the protein molecules
in the brain where they exert their effect. So in inorganic chemistry and organic
chemistry this detailed, precise knowledge of the exact structures of molecules began
to become more and more significant. I found that the old structure theory of the
organic chemists had flaws in it. There were some aspects of chemistry that just hadn't
been explained, understood. And by use of the new information about the structure
of the molecules and the theory of quantum mechanics, which explained, which permitted
one to make calculations as to what the electrons are doing in the molecules, I found,
and other people working in the same field of course contributed, found also that
it was possible to build up a very powerful theory of chemical structure that comes
into almost all the activities of scientists nowadays.
