The apparent vapor transport of OtAsF6 by sublimation at modest temperatures is shown to proceed via the reversible reaction, 0 l A s F ; e OzF' + AsF,, involving a free radical mechanism. This reaction path is in marked contrast to the vapor transport of OzPtF6, o2RuF6 and OzRhF6 species which proceed via dissociation and recombination with charge transfer, 0;PtF;a o2 + PtF6.The apparent molecular transfer and intact recovery of ionic hexafluorometallate salts such as O i P t F i by sublimation at modest temperatures and condensation on a cooled surface was originally interpreted as a simple molecular transport process. 1*2 Mass spectral ~t u d i e s ,~ however, demonstrated that reversible dissociation and recombination with charge transfer was involved:O i M F , e 0 2 + M F s (M=Pt, Ru, Rh) (1)For other dioxygenyl salts, OZMFZ and OiM2FTl (M = As, Sb, Nb and Ta), for which MF6 species are unlikely products, the overall stoichiometries were found to be3*4OlMF; + 0 2 + $FZ + MF5 (M = As, Sb)OiM2Fll + O2 +iF2 + 2MF5 (M = Sb, Nb, Ta, V) ( 3 )One problem with Eqns (2) and ( 3 ) is that they do not account for the transport of the dioxygenyl salts. The reverse of reactions (2) and ( 3 ) do not proceed at measurable rates at low temperatures; heat2 or photolytic initiation4 is necessary.