  We are studying the Na-O anticorrelation in several globular clusters of
different Horizontal Branch (HB) morphology in order to derive a possible
relation between (primordial) chemical inhomogeneities and morphological
parameters of the cluster population. We used the multifiber spectrograph
FLAMES on the ESO Very Large Telescope UT2 and derived atmospheric parameters
and elemental abundances of Fe, O and Na for about 150 red giant stars in the
Galactic globular cluster NGC 6752. The average metallicity we derive is
[Fe/H]=-1.56, in agreement with other results from red giants, but lower than
obtained for dwarfs or early subgiants. In NGC 6752 there is not much space for
an intrinsic spread in metallicity: on average, the rms scatter in [Fe/H] is
0.037+/-0.003 dex, while the scatter expected on the basis of the major error
sources is 0.039+/-0.003 dex. The distribution of stars along the Na-O
anticorrelation is different to what was found in the first paper of this
series for the globular cluster NGC 2808: in NGC 6752 it is skewed toward more
Na-poor stars, and it resembles more the one in M 13. Detailed modeling is
required to clarify whether this difference may explain the very different
distributions of stars along the HB.
