We present cross sections as a function of the collision energy for the bond-forming reactions of argon dications with oxygen molecules, producing ArO2++O and ArO++O+, respectively. Both the reactions are exothermic, and have cross sections much smaller than those of the competitive charge-transfer processes. The low-lying electronic states of ArO2+ have been calculated at the MR-AQCC/cc-pV5Z level. In contrast to previous results we found that the ground (3)Sigma(-) state has a local minimum. However, the estimated lifetime of this metastable state is too short to be detected in our setup. Thus the observed ArO2+ ions must be in the higher-lying (1)Delta or (1)Sigma(+) states. (C) 2003 American Institute of Physics.