Syntheses, crystal structures, resistivity studies, and electronic properties of three new barium actinide tellurides: BaThTe4, BaUTe4, and BaUTe6.
The 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)[AnTe4(2–)] layers separated by Ba(2+) 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 Te–Te interactions are longer than that of a Te–Te single bond. However, this structure also possesses Te–Te single bonds. Charge balance in the formula BaAnTe4 may be achieved with [Ba(2+)]2[(An(4+))2(Te(2–))2(Te2(2–))(Te2(3–))2](4–). The structure of BaUTe6 features one-dimensional anionic ∞(1)[UTe6(2–)] chains that are separated by Ba(2+) ions. There are three Te–Te single bonds around each U atom. The anion in this structure can thus be described as [U(4+)(Te2(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.
Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
Jai
J
Prakash
Sébastien
S
Lebègue
Christos D
CD
Malliakas
James A
JA
Ibers