Synthesis, Characterization, and Magnetic Properties of Uranium-Containing 2H-Perovskite-Related Sulfides: Ba 3 MUS 6 (M = Mn, Fe, Co, Ni) and Ba 3 Co 0.858(5) Mg 0.142(5) US 6 .

The uranium-containing 2H-perovskite-related chalcogenide family of compounds was revisited using the recently developed boron-chalcogen mixture (BCM) method for actinides to aid in their syntheses and to obtain magnetic measurements. Two known 2H-perovskite-related structures, Ba 3 MnUS 6 and Ba 3 FeUS 6 , were synthesized using the BCM method and were found to exhibit antiferromagnetic transitions at T N = ∼7.6 and 10.8 K, respectively. Combining the BCM method with the molten flux crystal growth technique resulted in single crystals of three new compositions, Ba 3 NiUS 6 , Ba 3 CoUS 6 , and Ba 3 Co 0.858(5) Mg 0.142(5) US 6 , the synthesis and characterization of which is reported. Magnetic measurements of Ba 3 NiUS 6 revealed a complex magnetic susceptibility consisting of a weak, glassy, antiferromagnetic transition near 65 K followed by an antiferromagnetic transition at T N = ∼18 K. A reduced radius ratio plot for the existing chalcogenide compositions and new additions to this structure type reported herein is presented to aid in the search for additional 2H-perovskite-related sulfides.