O-2(+) salts dissolved in liquid anhydrous hydrogen fluoride (aHF) at 20 degrees C or below oxidize aHF solutions of PtF62- to PtF6-. The parent base of O-2(+) salts in aHF (O2F(solv)) generated with alkali fluoride is:long-lived below -50 degrees C. An aHF solution of O2F(solv) oxidizes Au(III) to Au(V) below -50 degrees C (2O(2)F((solv)) + AuF4(solv-) --> AuF6(solv-) +2O(2(g))) In situ generation of O2F(solv) (O-2((solv)+) + F-(solv(-)) --> O2F(solv)) with AgF2 or NiF2 in suspension in the aHF made basic with alkali fluoride gives AgF4- and NiF(6)(2-)salts. Low solubility of AAsF(6)(A = Cs, K) in aHF provides for the metathetical preparation of (O-2)(2)PdF6 solutions in aHF. Removal of aHF, even at -60 degrees C, results in some O-2 and F-2 loss, to a composition approaching (O-2)PdF5.