Synthesis, crystal structure, and optical properties of Ba2Cu2ThS5, and electronic structures of Ba2Cu2ThS5 and Ba2Cu2US5

Journal of Solid State Chemistry

Beard

et al. 2015

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Synthesis, crystal structure, optical, and electronic study of the new ternary thorium selenide Ba 3 ThSe 3 (Se 2 ) 2 Journal of Solid State Chemistry, http://dx.Abstract The compound Ba 3 ThSe 3 (Se 2 ) 2 has been synthesized by solid-state methods at 1173 K. Its crystal structure features one dimensional chains of 1 ∞ [Th(Se) 3 (Se 2 ) 2 6− ] separated by Ba 2+ 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 pseudoocthedral geometry around Th. The Th−Se distances are consistent with Th 4+ and hence charge balance of Ba 3 ThSe 3 (Se 2 ) 2 is achieved as 3 × Ba 2+ , 1 × Th 4+ , 3 × Se 2− , and 2 × Se 2 2−. From optical measurements the band gap of Ba 3 ThSe 3 (Se 2 ) 2 is 1.96(2) eV.DFT calculations indicate that the compound is a semiconductor.

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Section: Introductionmentioning

confidence: 99%

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

Journal of Solid State Chemistry

Beard

et al. 2015

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“…There are relatively few quaternary actinide chalcogenides with [16], Ak 2 Cu 2 AnQ 5 (Ak ¼ Ba, Sr; An¼Th, U; Q ¼S, Se) [16][17][18], CsUMTe 5 (M ¼Ti [19] and Zr [20]), ATiU 3 Te 9 (A ¼Rb, Cs) [21], Cs 5 Hf 5 UTe 30.6 [19], Ba 2 MAnTe 7 (M ¼Ti, Cr; An¼Th, U) [22], and AMUQ 3 (A ¼Rb, Cs) [23]. The chemistry of these uranium chalcogenides is dominated by U 4 þ compounds.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, crystal structure, resistivity, and electronic structure of the U(V) quaternary polyselenide Ba8PdU2Se12(Se2)2

Journal of Solid State Chemistry

Lebègue

et al. 2015

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a b s t r a c tA new quaternary uranium(V) selenide, Ba 8 PdU 2 Se 12 (Se 2 ) 2 , has been synthesized by reaction of elements at 1173 K. A single-crystal X-ray diffraction study shows that the compound crystallizes in a new structure type with two formula units in space group D Pnnm 2h 12 -of the orthorhombic crystal system with cell constants of a ¼9.490(1), b ¼12.240(2), and c¼ 13.780(3) Å. Its crystal structure consists of ⎡ ⎣ ⎤ ⎦ PdU Se 2 12 12− units where U atoms are coordinated to six Se atoms in octahedral geometry and Pd atoms are coordinated to four Se atoms in square-planar geometry. These ⎡ ⎣ ⎤ ⎦ PdU Se 2 12 12− units are separated by Ba to result in a salt-like crystal structure. This compound also contains Se 2 2− dimers that are part of Ba coordination polyhedra. The formula charge balances as (Ba 2 þ ) 8 (Pd 2 þ )(U 5 þ ) 2 (Se 2 À ) 12 (Se 2 2− ) 2 . Theoretical calculations predict antiferromagnetic semiconducting behavior for this compound with a band gap of 1.6 eV. Temperature-dependent four-probe resistivity measurements on single crystal confirm the semiconducting nature with an activation energy of 0.18(1) eV.

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“…Among these compounds, the actinide (An) chalcogenides have also been extensively studied because of the interesting properties of the f orbitals and their potential interaction with d elements in multinary M/AnQ. Among these, we can cite: AMAnQ 3 (A ¼ alkali metal) [6e8], A 6 Cu 12 U 2 S 15 [9], Tl 3 Cu 4 USe 6 [10], KCuThS 3 , K 2 Cu 2 ThS 4 , K 3 Cu 3 Th 2 S 7 [11], K 2 Cu 3 US 5 [12], CsTiUTe 5 [13], Ba 2 Cu 2 AnS 5 [14,15], Ba 9 Ag 10 U 4 S 24 [16], Ba 3 MUS 6 (M ¼ Ba, Fe, Ag) [17], Ba 4 Cr 2 US 9 [18], and Ba 3 Hg 3 U 3 S 18 [19]. These compounds are mainly obtained through solid-state reactions using flux methods [20] or by direct combination of elements.…”

Section: Introductionmentioning

confidence: 99%

Syntheses, crystal structures, and electronic properties of Ba 8 Si 2 US 14 and Ba 8 SiFeUS 14

Lebègue

et al. 2015

Solid State Sciences

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