We report the room temperature synthesis and structural characterization of a mu(2)-hydroxo-bridged Pu-IV dimer obtained from an acidic nitric acid solution. The discrete Pu-2(OH)(2)(NO3)(6)(H2O)(4) moiety crystallized with two distinct crystal structures, [Pu-2(OH)(2)(NO3)(6)(H2O)(4)](2)11H(2)O (1) and Pu-2(OH)(2)(NO3)(6)(H2O)(4)2H(2)O (2), which differ primarily in the number of incorporated water molecules. High-energy X-ray scattering (HEXS) data obtained from the mother liquor showed evidence of a correlation at 3.7(1) A but only after concentration of the stock solution. This distance is consistent with the dihydroxo-bridged distance of 3.799(1) A seen in the solid-state structure as well as with the known Pu-Pu distance in PuO2. The structural characterization of a dihydroxo-bridged Pu moiety is discussed in terms of its relevance to the underlying mechanisms of tetravalent metal-ion condensation.