Spectra are reported of an unidentified oxygen molecule center of monoclinic symmetry found in natural crystals of CaF₂. Two alternative models consisting of a perturbed O₂^- and a O₃^- molecule ion substituting for two fluorine neighbors are discussed. In contrast to the well-known unperturbed O₂^- center in CaF₂, this new center has a visible absorption band. This band exhibits vibronic structure corresponding to an excited-state vibrational frequency of (900 ± 10) cm^-1 and coupling constants S ≃ 6 for this vibration and S ≥ 6 for the lattice phonons. This structure is enhanced in stress-induced dichroism spectra. Resonance Raman scattering excited in this band shows the ground-state vibrational fundamental at (1038 ± 1) cm^-1 and the overtone at (2076 ± 2) cm^-1. The polarization of these features is consistent with the <100> orientation of the center. The Lorentzian line-shape, the width, and the relative intensity of the two- and one-phonon scattering peaks are consistent with recent theories of the resonant Raman effect of impurity centers.