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 S2 2- 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.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry