  We present the first fluorine measurements in 12 normal giants belonging to
the Galactic thin and thick disks using spectra obtained with the Phoenix
infrared spectrometer on the 2.1m telescope at Kitt Peak. Abundances are
determined from the (1-0) R9 2.3358 micron feature of the molecule HF.
Additionally, sodium abundances are derived in 25 giants in the thin disk,
thick disk, and halo using the Na I line at 2.3379 microns. We report fluorine
abundances for thin and thick disk stars in the metallicity range -0.7 < [Fe/H]
< 0. We add two abundance measurements for stars with [Fe/H] < 0.5 dex which
are at a critical metallicity range to constrain models. We find a larger
dispersion in fluorine abundances than sodium abundances despite both species
having similar overall uncertainties due to atmospheric parameters, suggesting
this dispersion is real and not observational. The dispersion is slightly
larger in the thick disk than the thin. The thin and thick disk average [F/Fe]
for our sample of stars combined with the literature differ by 0.03 dex. The
observations are compared to available chemical evolution models.
