Synthesis, crystal structure, optical, and electronic study of the new ternary thorium selenide Ba3ThSe3(Se2)2

• Ba3ThSe3(Se2)2 has been synthesized by solid-state methods at 1173 K.
• The structure features chains of 1∞[Th(Se)3(Se2)26−] separated by Ba2+ cations.
• Ba3ThSe3(Se2)2 is a semiconductor with a band gap of 1.96(2) eV.

The compound Ba3ThSe3(Se2)2 has been synthesized by solid-state methods at 1173 K. Its crystal structure features one-dimensional chains of 1∞[Th(Se)3(Se2)26−] 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(Se2)2 is achieved as 3×Ba2+, 1×Th4+, 3×Se2−, and 2×Se22−. From optical measurements the band gap of Ba3ThSe3(Se2)2 is 1.96(2) eV. DFT calculations indicate that the compound is a semiconductor.

Local coordination environment of Th atoms in the Ba3ThSe3(Se2)2 structure.Figure optionsDownload as PowerPoint slide