The conformation of a
molecule refers to the relative positions of individual atoms of the molecule.
Steric and
electronic factors will determine what conformation is the most stable for a molecule.
The simplest molecule for study of conformation is n-butane. One can picture this molecule turning between the two following forms (only the carbon skeleton is shown; all carbon atoms in same plane):
C C
\ /
C-C "eclipsed"
C
\
C-C "staggered"
\
C
In the eclipsed form, the hydrogen atoms from the
terminal carbon atoms are "bumping" each other. This bumping does not exist in the staggered conformation. On this basis alone, we can determine that the staggered conformation of n-butane would be more stable. This would be correct. The
energy difference between these conformations for this molecule is small, as the steric interaction between the terminal carbons is minimal, but the staggered conformation is more stable, and the molecule would be expected to spend more time in this form.
For more complicated molecules, studies of conformation take on monumental proportion. The folding of proteins largely determines their ability to perform as designed. Conformational changes of proteins can cause disease, as in the case of prions.