First Organic–Inorganic Uranyl Chloroselenate: Synthesis, Crystal Structure and Spectroscopic Characteristics

Single crystals of the new uranyl selenate hydrate (C5H12NO)[(UO2)(SeO4)Cl(H2O)] (1) have been prepared by evaporation at room temperature from aqueous solution of uranyl nitrate, selenic acid, potassium hydroxide and choline chloride. The crystal structure of 1 has been solved by direct methods [monoclinic, P21/n, a = 10.745(4), b = 11.236(4), c = 12.477(4) A, β = 114.580(5)°, V = 1,369.9(8) A3, Z = 4] and refined to R 1 = 0.022 (wR 2 = 0.058) for 4,350 reflections with |Fo| ≥ 4σ F using least square techniques. The structure is based upon the [(UO2)(SeO4)Cl(H2O)]− layers consisting of UO6Cl pentagonal bypyramids sharing corners with SeO4 tetrahedra. The presence of the Cl− ions in the system leads to the formation of a mixed-ligand coordination of uranyl ions. The topology of the 2D layer in the structure of 1 is based upon 4- and 8-membered rings of polyhedra and is related to the one observed in the structure of apophyllite-group minerals. Single crystals of the new uranyl selenate chloride (C5H12NO)[(UO2)(SeO4)Cl(H2O)] have been prepared by evaporation at room temperature; the structure based upon 2D [(UO2)(SeO4)Cl(H2O)]− units whereas uranyl ions are coordinated by both O atoms of selenate anions and Cl atoms and description of its unprecedented structural topology reported herein.