Electrode reactions of monovalent and trivalent bromoaurates, [(AuBr2)-Br-I] and [(AuBr4)-Br-III](-), have been investigated in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide. [(AuBr4)-Br-III] could be reduced to metallic Au via an intermediate species, [(AuBr2)-B-I](-), which was stable in the ionic liquid. [(AuBr2)-B-I](-) could be prepared by a proportionation reaction of [(AuBr4)-B-III](-) and Au in the ionic liquid. Although metallic Au was deposited on a glassy carbon substrate at -1.5 V vs. Ag/Ag(I), Au nano-particles with an average diameter of (2.6 +/- 0.6) nm were formed and dispersed in the ionic liquid by potentiostatic cathodic reduction on a glassy carbon electrode at -2.5 V vs. Ag/Ag(I). (C) 2013 The Electrochemical Society. All rights reserved.