ABSTRACT
The Group 11 is composed of copper (Cu), silver (Ag), and gold (Au). Ag and Au belong to the so-called noble metals. All these metals occur in variable oxidation stages, mainly +1 and +2 (Table 16.1). Cu and Ag reveal chalcophilic tendencies whereas Au is siderophilic. The terrestrial abundance of Cu is very well documented, whereas data for Ag and Au occurrence are rather scarce (Table 16.1).
