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Overview
“Organic chemistry! Puzzle chemistry! Stink
chemistry! Drugstore chemistry! … organic chemistry, that
is a trade for pot-washers.”
[from Sinclair Lewis’ “Arrowsmith”,
The Modern Library, NY, 1933]
One of the true marvels of science is that 19th
chemists were able to deduce molecular structures long before 20th
century chemists learned to “look inside” molecules
and measure atom positions. Perhaps a greater marvel is the fact
that we still make routine use of their ideas about structure and
bonding.
Nevertheless, chemistry has witnessed great changes
in the way chemists think about structure. Once upon a time, it
may have been enough to know which atom was bonded to which, but
today’s chemists need more information than that. The design
of modern medicines, fuels, and so on, relies heavily on quantitative
knowledge of molecular geometries. Consequently, the 19th
century caricature of an organic chemist as a mixer of “potions”
and “stinks”, is rapidly being replaced by one in which
the chemist is a “designer”, “architect”,
“sculptor”, and “builder” of molecules.
This chapter gives you a brief taste of one aspect
of molecular geometry, interatomic distance. As you will
see, the distance between two atoms depends on the presence of a
chemical bond between the atoms. Distance data can be used to locate
bonds within molecules, identify the type of bond, and even characterize
forces between different molecules.
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