Three new rubidium polychromates, Rb₂[(UO₂) (Cr₂O₇)(NO₃)₂] (1), γ-Rb₂Cr₃O₁₀ (2) and δ-Rb₂Cr₃O₁₀ (3) were prepared by combination of hydrothermal treatment at 220 °C and evaporation of aqueous solutions under ambient conditions. Compound 1 is monoclinic, P2₁/c, a = 13.6542(19), b = 19.698(3), c = 11.6984(17) Å, β = 114.326(2)°, V = 2867.0(7) ų, R₁ = 0.040; 2 is hexagonal, P6₃/m, a = 11.991(2), c = 12.828(3) Å, γ = 120°, V = 1597.3(5) ų, R₁ = 0.031; 3 is monoclinic, P2₁/n, a = 7.446(3), b = 18.194(6), c = 7.848(3) Å, β = 99.953(9)°, V = 1047.3(7) ų, R₁ = 0.037. In the crystal structure of 1, UO₈ bipyramids and NO₃ groups share edges to form [(UO₂)(NO₃)₂] species which share common corners with dichromate Cr₂O₇ groups producing novel type of uranyl dichromate chains [(UO₂)(Cr₂O₇)(NO₃)₂]²⁻. In the structures of new Rb₂Cr₃O₁₀ polymorphs, CrO₄ tetrahedra share vertices to form Cr₃O₁₀²⁻ species. The trichromate groups are aligned along the 6₃ screw axis forming channels running in the ab plane in the structure of 2. The Rb cations reside between the channels and in their centers completing the structure. The trichromate anions are linked by the Rb⁺ cations into a 3D framework in the structure of 3. Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems is discussed.