ON THE CHEMICAL-STATE OF COMBINED GOLD IN SULFIDIC ORES - CONCLUSIONSFROM MOSSBAUER SOURCE EXPERIMENTS

Mossbauer experiments using the 77 keV resonance in Au-197 were perfor med with sources of PtX(2) chalcogenides and pnictides (X = S, Se, Te, As, Sb, and Bi). The isomer shifts and electric quadrupole interactio ns observed for gold on platinum sites in these materials support the idea that the chemically bound gold observed in the lattices of pyrite and arsenopyrite occupies iron sites. Moreover, in pyrite the gold ap pears to attract arsenic impurities into its immediate neighbourhood.