Synthesis, crystal structure, optical, and electronic study of the new ternary thorium selenide Ba3ThSe3(Se-2)(2)

International audienceThe compound Ba3ThSe3(Se-2)(2) has been synthesized by solid-state methods at 1173 K. Its crystal structure features one-dimensional chains of (1)(infinity)[Th(Se)(3)(Se-2)(2)(6-)] separated by Ba2+ cations. Each Th atom in these chains is coordinated to two Se-Se single-bonded pairs and four Se atoms to give rise to a pseudooctahedral geometry around Th. The Th-Se distances are consistent with Th4+ and hence charge balance of Ba3ThSe3(Se-2)(2) is achieved as 3 x Ba2+, 1 x Th4+, 3 x Se2-, and 2 x Se-2(2-). From optical measurements the band gap of Ba3ThSe3(Se-2)(2) is 1.96(2) eV. DFT calculations indicate that the compound is a semiconductor