A new wheel-shaped polyoxometalate {[W5O21](3)[((UO2)-O-VI)(2)(mu-O-2)](3)}(30-) has been synthesized and structurally characterized. The calculated electrostatic potential reveals the protonation of several mu-oxo bridges reducing the polyoxometalate total charge. A protonated structure computed at the density functional level of theory (DFT) is in good agreement with the experimental fit. This species presents a classical polyoxometalate electronic structure with well-defined metal and oxo bands belonging to its U/W and oxo/peroxo constituents, respectively. Furthermore, fragment calculations indicate that the electronic structures of the uranyl-peroxide and polyoxotugstate fragments are little affected by the nanowheel assembly.