· The common mining practice until very recently could be summarized in a few steps: from obtaining a license, dig the ore, sell the metal, and, once the deposit was exhausted, walkaway and start another mine elsewhere (Jain et al. 2016; EB 2017 ). Not surprisingly, mining is among the human activities with widest environmental and social impacts.
Gold(I) has the closed shell 4f145d 10 electronic configuration, and therefore gold(I) complexes are diamagnetic and adopt regular structures. All known gold(III) complexes have the lowspin 4P45d8 electronic con figuration and are also diamagnetic. The preferred coordination number of gold(I) is 2 and that of gold(III)