Synthesis, Crystal Structure, Theoretical, and Resistivity Study of BaUSe₃

Abstract

The black-colored compound BaUSe3 has been synthesized at 1173 K by a stoichiometric reaction of the elements in a CsCl flux. BaUSe3 crystallizes in the GdFeO3 structure type. There is no change in structure between 100 and 298 K. The U atoms in this structure are octahedrally connected to six Se atoms. Each octahedral unit shares all six corners with neighboring octahedra, forming a three-dimensional network. BaUSe3 can be charge balanced as Ba(2+)U(4+)(Se(2-))3. DFT electronic structure calculations found BaUSe3 to be antiferromagnetic in its ground state and to be a semiconductor with a band gap of 2.5 eV. The band gap is inconsistent with the black color of the material and with the small activation energy of 0.12(1) eV obtained from resistivity measurements. A UV-vis spectrum indicated that there was no band gap above 1 eV. It is possible that, for BaUSe3, intrinsic and extrinsic impurities from the flux create midgap states that lead to the experimentally measured narrow optical gap. More likely, BaUSe3 presents a challenge to DFT calculations as applied to 5f materials.

PbGa4S7: a wide-gap nonlinear optical material

“…Simultaneously, as demonstrated in the [Ga3S 4 ] tetrahedra (Fig. 2 distances vary from 2.742(3) to 3.533(3) Å, which are comparable to those observed in related compounds, such as Pb 4 Ga 4 GeS 12 (2.827(5) to 3.375(4) Å), 20 and PbU 2 S 5 (2.786(16) to 3.103 (16) Å), 57 and the calculated BVS 55 value is 1.697, close to the expected value of 2.000. The structure of PbGa 4 S 7 is illustrated in Fig.…”

Chalcogenide Perovskites: Tantalizing Prospects, Challenging Materials

“…Selenides: Only a few ABSe 3 combinations have with certainty been synthesized in the perovskite phase with GdFeO 3 ‐type symmetry, and all of them contain uranium [ 107–109 ] or thorium. [ 110 ] Obviously, application of such compounds in solar cells would not be practical.…”

Li2MnSnSe4: A New Quaternary Diamond‐Like Semiconductor with Nonlinear Optical Response and Antiferromagnetic Property

“…;Q= S, Se, Te ), polar units centered by the second-order Jahn-Teller-distorted d 0 cations (Zr 4 + ,N b 5 + ,T a 5 + ), cations with stereochemically active lonepair electrons (e.g.,A s 3 + ,S n 2 + ,P b 2 + ), and trigonal-planar units (BS 3 ,HgSe 3 ). [5] To date, by introducing one or more microscopic NLO units into one structure, many new chalcogenides with intriguing properties such as strong NLO responses andw ide band gaps (higher LDTsa re usually accessible in compounds with wider band gaps) have been discovered, such as LiGaQ 2 (Q = S, Se), [6] Li 2 In 2 MS 6 (M = Si, Ge), [5c] Li 2 CdMS 4 (M = Ge, Sn), [7] BaGa 4 Q 7 (Q = S, Se), [5a, b] BaGa 2 MSe 6 (M = Si, Ge;Q = S, Se), [5d] BaGa 2 SnSe 6 , [5j] AGa 4 S 7 (A = Sn, Pb), [5e, f] and Ln 4 GaSbS 9 (Ln = Pr, Nd, Sm, Gd-Ho). [8] Among av ariety of NLO compounds, Li-containingq uaternary DLSs drew our attention.…”