Structure of Cs2[(UO2)2F6(H2O)2] crystals

A Dinuclear Uranium Complex [{UO2F2(NH3)}2(μ‐F)2]2− from Reaction of TlF and UO2F2 in Liquid Anhydrous Ammonia and Fluoride Ion Affinities for Some Uranyl(VI) Species [UO2Fx]2−x and [UO2Fx(NH3)5−x]2−x

“…2À anion. [8,23] The DFT calculated bond lengths agree with 2.217-2.226 Å. In comparison to the terminally bound F atoms, the bridging μ-F atoms show, due to their higher coordination number, elongated UÀ (μ-F) bond lengths of 2.356(2) and 2.357 As also in many other ammine compounds, hydrogen bonds are present, leading to additional interactions between the constituting ions.…”

“…[8][9][10]21] The U�O distances agree with 1.787(3) and 1.796(3) Å compared to 1.781 and 1.783 Å in the [{UO 2 F 2 (H 2 O)} 2 (μ-F) 2 ] 2À anion and to 1.772(3) and 1.784(2) Å in the compound [UO 2 F 2 (NH 3 ) 3 ] 2 • 2NH 3 . [8,23] Despite the coordination of one of the O atoms to a Tl + cation, we observe no significant lengthening of the U�O bond. 2À anion.…”

“…. [22][23][24][25][26] Bis(triamminethallium(I)) di(μ-fluorido)bis(amminedifluoridodioxidouranate(VI)), [Tl 2 (NH 3 ) 6 ][{UO 2 F 2 (NH 3 )} 2 (μ-F) 2 ], crystallizes in the triclinic crystal system, in space group P � 1 (no. 2) with the lattice parameters a = 8.1547 (5), b = 8.3371(4), c = 8.8667(5) Å, α = 62.177(2)°, β = 69.676(2)°, γ = 87.666(2)°, V = 494.55(5) Å 3 and Z = 1, at 100 K. For details of the structure determination and selected crystallographic data see Table 1 and the Supporting Information.…”

“…The [{UO 2 F 2 (NH 3 )} 2 (μ‐F) 2 ] 2− anion presented here is one of the few examples of an ammine complex where the corresponding aqua complex is known which had been obtained as the Cs salt in the crystalline compound Cs 2 [{UO 2 F 2 (H 2 O)} 2 (μ‐F) 2 ] [22–26] …”

Systematic DFT Study of Gas Phase and Solvated Uranyl and Neptunyl Complexes [AnO2X4]n (An = U, Np; X = F, Cl, OH, n = −2; X = H2O, n = +2)

“…Thus, the formal [UO 2 F 4 ] 2- species in solution actually contains an aqua ligand in the first coordination shell, [UO 2 F 4 (H 2 O)] 2- . In the experimentally characterized structures of solid fluoride systems, the coordination number is five, as well; − crystal structures often contain coordinated (inner sphere) water or bridging F atoms connecting UO 2 F 5 pentagonal bipyramids, like in the dimer [U 2 O 4 F 8 ] 4- occurring in (C 4 N 2 H 12 )UO 2 F 4 ·3H 2 O molecular phases . We can nevertheless compare our calculated U−F bond lengths to the terminal ones of the [U 2 O 4 F 8 ] 4- dimer and also to the EXAFS values for [UO 2 F 4 (H 2 O)] 2- in aqueous solution, which agree with each other within 0.02 Å.…”