Chemical Abundance Variations in Globular Clusters: Recent Results from Mildly Metal-Poor M5

We present a chemical composition analysis of 36 giant stars in mildly metal-poor globular cluster M5. In comparing the M5 results to those obtained in M4, a cluster previously considered to be a twin'' in age, metallicity and chemical composition, we find large star-to-star variations in the abundances of elements sensitive to proton-capture nucleosynthesis, similar [Fe/H] values, but factor of two differences in some alpha-capture, odd-Z and slow neutron-capture process elements. Among stars in globular clusters, apparently there are no definitive single’’ values of [el/Fe] at a given [Fe/H] for many important elements.