Crystal-Chemical Features of U(VI) Compounds with Inorganic Complexes Derived from [(UO2)(TO4)(H2O)n], T = S, Cr, Se: Synthesis and Crystal Structures of Two New Uranyl Sulfates

Abstract

Two new U(VI) sulfates, [CH6N3]2(NO3)2[(UO2)(SO4)(H2O)2]·H2O (1) and [C5H8N2]2[(UO2)· (SO4)2] (2), were prepared by isothermal evaporation from aqueous solutions. Compound 1 crystallizes in the monoclinic system, space group P21/n, a = 12.3824(7), b = 7.0329(4), c = 21.5362(12) A, β = 99.598(2)°, and compound 2, in the triclinic system, space group P1, a = 7.0126(9), b = 10.3352(13), c = 13.8027(19) A, α = 68.187(5)°, β = 78.940(5)°, γ = 71.339(3)°. The crystal structure of the compounds was studied at 100 K. The structures were solved by direct methods and refined to R1 = 0.059 and 0.032 for 1 and 2, respectively. The structure of 1 is based on electrically neutral [(UO2)(SO4)(H2O)2]0 chains between which protonated guanidine molecules, NO 3 – anions, and water molecules are located. In compound 2, protonated molecules of 4-aminopyridine bind [(UO2)(SO4)2]2– chains in a three-dimensional structure. Specific crystal-chemical features of chain U(VI) compounds with tetrahedral oxoanions, derived from [(UO2)(TO4)(H2O)n], T = S, Cr, Se, are considered.