Ternary Chalcogenides BaMTe (M = Cu, Ag): Syntheses, Modulated Crystal Structures, Optical Properties, and Electronic Calculations.

Standard solid-state methods produced black crystals of the compounds BaCuTe and BaAgTe at 1173 K; the crystal structures of each were established using single-crystal X-ray diffraction data. Both crystal structures are modulated. The compound BaCuTe crystallizes in the monoclinic superspace group 2(1/2)0, having cell dimensions of = 4.

Modulated Linear Tellurium Chains in BaScTe: Synthesis, Crystal Structure, Optical and Resistivity Studies, and Electronic Structure.

A new ternary telluride, BaScTe, with a pseudo-one-dimensional structure, was synthesized at 1173 K by standard solid-state methods. A single-crystal X-ray diffraction study at 100(2) K shows the structure to be modulated. The structure of the subcell of BaScTe crystallizes with two formula units in the hexagonal space group -6/ with unit cell dimensions of = = 10.

NpSe : a Binary Chalcogenide Containing Modulated Selenide Chains and Ambiguous-Valent Metal.

A new binary compound, NpSe possesses metal-chalcogen and chalcogen-chalcogen interactions different from those reported for other metal dichalcogenides. Its structure is incommensurately modulated and features linear Se chains and valence-ambiguous Np cations.

Synthesis and Characterization of BaAgSe(Se).

Single crystals and a polycrystalline sample of BaAgSe(Se) were synthesized by standard solid-state chemistry methods at 1173 and 973 K, respectively. The crystal structure of this ternary compound was established by single-crystal X-ray diffraction studies at 100(2) K. The superstructure of this compound is commensurate and crystallizes in the space group P2/ c of a monoclinic system with cell constants of a = 6.

AgU(PS): A Transition-Metal Actinide Phosphochalcogenide.

The structure of AgU(PS) is unique, as in the literature there are no other structures of the type MAnPQ (M = transition metal, An = actinide, Q = S, Se, or Te). The compound has been synthesized at 1123 K by standard solid-state methods, and its single-crystal X-ray structure has been determined at 100(2) K. AgU(PS) crystallizes in a remarkable new structure type in space group P321 of the trigonal system with three formula units in a hexagonal cell of dimensions a = b = 9.