Syntheses, Crystal Structures, Resistivity Studies, and Electronic Properties of Three New Barium Actinide Tellurides: BaThTe4, BaUTe4, and BaUTe6

International audienceThe three new solid-state compounds BaThTe4, BaUTe4, and BaUTe6 have been synthesized and characterized. BaThTe4 and BaUTe4 are isostructural. The structure consists of infinite (2)(infinity)[AnTe4(2-)] layers separated by Ba2+ ions. Each An (An = Th, U) atom is coordinated to eight Te atoms in a bicapped trigonal-prismatic arrangement. Te atoms are connected to each other to form linear infinite chains. These TeTe interactions are longer than that of a TeTe single bond. However, this structure also possesses TeTe single bonds. Charge balance in the formula BaAnTe(4) may be achieved with [Ba2+](2)[(An(4+))(2)(Te-2)(2)(Te2(2))(Te-2(3))(2)](4). The structure of BaUTe6 features one-dimensional anionic (1)(infinity)[UTe62] chains that are separated by Ba2+ ions. There are three TeTe single bonds around each U atom. The anion in this structure can thus be described as [U4+(Te-2(2))(3)](2). Resistivity measurements on single crystals of BaThTe4 and BaUTe6 show semiconducting behavior. DFT calculations indicate finite band gaps for BaThTe4 and for BaUTe6, whereas BaUTe4 has a vanishing density of states at the Fermi level