The mobility and transport of gold in hydrothermal vapors is strongly influenced by the molecular speciation of gold, which is highly sensitive to pH, oxidation state and water vapor pressure. In this study, electrospray ionization mass spectrometry (ESI-MS) and ab initio tools are applied to examine the composition, structure and stability of gold chloride clusters. In brief, electrospray ionization of aqueous AuCl3 solutions leads to mononuclear clusters of the general form [AuCl2]+(H2O)n (n=0-4), [AuOHCl]+(H2O)n (n=0-1) and [AuCl2]+(HCl)2(H2O)n (n=0-4). Additionally, ion signals due to the dinuclear species [Au2Cl5-xOHx]+(H2O)n (x=0-1) are present …postprin
