  We present a detailed analysis of IC 4776, a planetary nebula displaying a
morphology believed to be typical of central star binarity. The nebula is shown
to comprise a compact hourglass-shaped central region and a pair of precessing
jet-like structures. Time-resolved spectroscopy of its central star reveals
periodic radial velocity variability consistent with a binary system. While the
data are insufficient to accurately determine the parameters of the binary, the
most likely solutions indicate that the secondary is probably a low-mass main
sequence star. An empirical analysis of the chemical abundances in IC 4776
indicates that the common-envelope phase may have cut short the AGB evolution
of the progenitor. Abundances calculated from recombination lines are found to
be discrepant by a factor of approximately two relative to those calculated
using collisionally excited lines, suggesting a possible correlation between
low abundance discrepancy factors and intermediate-period post-common-envelope
central stars and/or Wolf-Rayet central stars. The detection of a radial
velocity variability associated with binarity in the central star of IC 4776
may be indicative of a significant population of (intermediate-period)
post-common-envelope binary central stars which would be undetected by classic
photometric monitoring techniques.
