Isolated Uranyl Chromate and Polychromate Units in Crown Ether Templated Compounds

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)(infinity)[(UO2)(CrO4)(H2O)(3)] units formed by the bidentate character of the edge sharing UrO(5) 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.