Copper and Zinc Abundances in Metal-Poor Stars

We present preliminary results of our recent effort devoted to the determination of copper and zinc abundances in a large sampIe of stars of the Galactic halo. By adding several new data points at very low metallicity, we aim at better constraining the [Cu/Fe] and [Zn/Fe] trends below [Fe/H]= -2.5. The very few Cu and Zn data points currently available below this metallicity [11], are not sufficient to draw firm conclusions. A deeper knowledge of the nucleosynthetic origin of these two elements is necessary to clarify whether copper and zinc should be considered the heaviest of the iron-group elements, or the lightest of the neutron-capture elements.