Harnessing the nominally terminal oxo atoms of the linear uranyl (UO22+) cation represents a frontier within the field of f-element hybrid materials. Here we outline a route for systematically accessing uranyl oxo atoms via judicious pairing with Ag+ cations or iodobenzoates, and describe the syntheses and crystal structures of four new heterometallic compounds containing Ag+ cations, the UO22+ cation, and o- (1), m- (2), p-iodo- (3), and 2,5-diiodo- (4) carboxylate ligands. Vibrational and luminescence spectroscopic properties for all four compounds are reported, as are computational findings from quantum chemical calculations and density-based quantum theory of atoms in molecules (QTAIM) analyses. Single crystal X-ray diffraction analysis of compounds 1-4 shows that the nominally terminal uranyl oxo atoms are engaged in either covalent UO2-Ag cation-cation interactions (1 and 3) or non-covalent assembly via halogen bonding interactions (2 and 4). Raman, infrared (IR), and luminescence spectra of 1-4 are redshifted with respect to the free uranyl cation indicating that both halogen-oxo and cation-cation interactions weaken the UO bond, and in the case of 3 we note a rare example of activation of the uranyl asymmetric stretch (ν3) in the Raman spectra, likely due to the Ag-oxo cation-cation interaction lowering the symmetry of the uranyl cation. Quantum chemical calculations and QTAIM analysis highlight a quantitative difference between halogen bonds and cation-cation interactions, with the latter shown to significantly decrease uranyl bond orders and electron density at bond critical points.