The compound Ba 8Hg 3U 3S 18 was obtained from the solid-state reaction at 1123 K of U, HgS, BaS, and S, with BaBr 2/KBr or BaCl 2 as a flux. This material crystallizes in a new structure type in space group P6̄ of the hexagonal system with three formula units in a cell of dimensions a = 27.08(1) Å, c = 4.208(2) Å, and V = 2673(2) Å 3. The structure contains infinite chains of US 6 octahedra and nearly linear [S-Hg-S] 2- dithiomercurate anions, separated by Ba 2+ cations. In the temperature range 100-300 K, the paramagnetic behavior of Ba 8Hg 3U 3S 18 can be fit to the Curie-Weiss law, resulting in μ eff = 5.40(4) μ B, or 3.12(2) μ B/U. The compound displays an antiferromagnetic transition at T N = 59 K. Although the formal oxidation states of Ba, Hg, and S can be assigned as +2, +2, and -2, the oxidation state of U is less certain. On the basis of interatomic distance arguments and the magnetic susceptibility data, the compound is proposed to contain U in both +4 and +5 formal oxidation states.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry