Two compounds containing isolated uranyl chromate and polychromate units were synthesized through room-temperature reactions of uranyl nitrate, chromium(VI) oxide, and 18-crown-6/15-crown-5 in aqueous solutions. Uranyl chromate with 18-crown-6 consists of neutral _∞ ⁰[(UO₂)(CrO₄)(H₂O)₃] units formed by the bidentate character of the edge sharing UrO₅ bipyramid with only CrO₄ and organic molecules and no additional crystallization water molecules. Uranyl polychromate with 15-crown-5 is the first inorganic compound in which [CrO₄]^2-, [Cr₂O₇]^2-, and [Cr₃O₁₀]^2- chromate groups are observed simultaneously.