Laser-ablated Tl atoms react with Oz to give a new linear insertion product OTlO and the dimer TlOTlO in addition to the cyclic Tl(O-2), TlO2Tl, and Tl4O2 products observed in earlier thermal effusion experiments. Molecular assignments are based on matrix infrared spectra of oxygen isotopic species. Infrared spectroscopic and quantum chemical evidence is presented for the cyclic molecular anion Tl(O-2)(-). Analogous absorptions in Ga and In experiments are assigned to Ga(O-2)(-) and In(O-2)(-) on the basis of new experiments using a positively biased electrode near the sample and quantum chemical calculations.