By treating gaseous, liquid, or solid fluorides with UV-photolyzed O-2/F-2 mixtures and by treating solid oxides with UV-photolyzed F-2 (or O-2/F-2 mixtures) in liquid anhydrous HF at ambient temperature, we investigated the possibility of the preparation of (O2MF4)-F-III (M = B, Fe, Co, Ag), (O2MF5)-F-IV (M = Ti, Sn, Pb), (O-2)(2)(MF6)-F-IV (M = Ti, Ge, Sn, Pb, Pd, Ni, Mn), (O2M2F9)-F-IV (M = Sn), (O2MF6)-F-V (M = As, Sb, Au, Pt), (O2M2F11)-F-V (M = Pt), (O2MF7)-F-VI (M = Se), (O-2)(2)(MF8)-F-VI (M = Mo, W), and (O2MF8)-F-VII (M = I). The approach has been successful in the case of previously known O2BF4, O2MF6 (M = As, Sb, Au; Pt), O2GeF5, and (O-2)(2)(Ti7F30). Novel compounds O2GeF5 center dot HF, alpha-O2Sn2F9 (1-D), and the HF-solvated and nonsolvated forms of beta-O2Sn2F9 (2-D) were synthesized and their crystal structures determined using single-crystal X-ray diffraction. The crystal structures of all of these materials arise from the condensation of octahedral MF6 (M = Ge, Sn) units. The anion in the crystal structure of O2GeF5 center dot HF is comprised of infinite ([GeF5](-))(infinity) chains of GeF6 octahedra that share common vertices. The HF molecules and O-2(+) cations are located between the chains. The crystal structure of alpha-O2SnF9 (1-D) is constructed from [O-2](+) cations and polymeric ([Sn2F9](-))(infinity) anions which appear as two parallel infinite chains comprised of SnF6 units, where each SnF6 unit of one chain is connected to a SnF6 unit of the second chain through a shared fluorine vertex. The singlecrystal structure determination of [O-2][Sn2F9]center dot 0.9HF reveals that it is comprised of two-dimensional ([Sn2F9](-))(infinity), grids with [O-2](+) cations and HF molecules located between them. The 2-D grids have a wavelike conformation. The ([Sn2F9](-))(infinity), layer contains both six- and seven-coordinated Sn(IV) atoms that are interconnected by bridging fluorine atoms. A new, more complex [O-2](+) salt, O-2[Hg(HF)](4)[SbF6](9), was prepared. In its crystal structure, the Hg atoms bridge to SbF6 units to form a 3-D framework. The O-2(+) cations are located inside the voids while the HF molecules are bound to Hg atoms through the F atom. Attempts to prepare several chlorine analogues of O-2(+) fluorine salts (i.e., O2TiCl5 and O2MCl6 (M = Nb, Sb)) failed.