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Nice article, very good in historical data. Unfortunately, the chemistry is weak. The role of chloride ions is not to "make room for more gold ions" but to change the potential of the redox reaction. The electrode potential of nitric acid reduction is 0.96 while the oxidation of gold to Au+3 is 1.52, therefore it is not spontaneous. On the other hand, the oxidation to Au(Cl-)4 has a potential of only 0.93 V, because the equilibrium shifts the potential. Therefore, the dissolution of gold in aqua regia is spontaneous (note that high Cl- concentration increaes the cell voltage).