The [U₂(μ-S₂)₂Cl₈]^4–Anion: Synthesis and Characterization of the Uranium Double Salt Cs₅[U₂(μ-S₂)₂Cl₈]I

Abstract

Red plates of Cs5[U2(μ-S2)2Cl8]I were obtained in good yield from the reaction at 1173 K of U, GeI2 or SnI4, and S, with CsCl flux. The compound crystallizes in space group D2h25-Immm of the orthorhombic system in the Cs5[Nb2(μ-S2)2Cl8]Cl structure type. The centrosymmetric [U2(μ-S2)2Cl8]4– anion in the structure has mmm symmetry with the two U4+ atoms separated by 3.747(1) Å. Each U atom is coordinated to four Cl atoms and four S atoms from two S22– groups in a square-antiprismatic arrangement. The polarized absorbance spectra of Cs5[U2(μ-S2)2Cl8]I display prominent optical anisotropy. Magnetic measurements are consistent with the modified Curie–Weiss law at high temperatures. The low-temperature behavior may arise from antiferromagnetic coupling of the U4+ ions within the anion.

Ba2AsGaSe5: A New Quaternary Selenide with the Novel [AsGaSe5]4– Cluster and Interesting Photocatalytic Properties

“…In recently years, many interesting and more complex anions have been discovered as a result of the development of the synthesis methods . For example, the novel uranyl sulfide Na 2 Ba 2 (UO 2 )­S 4 comprises isolated centrosymmetric [(UO 2 )­S 4 ] 6– anions that are surrounded by Na + and Ba 2+ cations and Cs 5 [U 2 (μ-S 2 ) 2 Cl 8 ]­I contains the [U 2 (μ-S 2 ) 2 Cl 8 ] 4– anion with two US 4 Cl 4 square antiprisms sharing two common S 2 2– anions, while Cs 5 P 5 Se 12 contains [P 5 Se 12 ] 5– anions featuring an octahedrally coordinated P 3+ cation surrounded by two ethane-like [P 2 Se 6 ] 4– units and exhibits a second harmonic generation response.…”