Tlchalcogenide

Tlchalcogenide refers to a class of compounds formed from thallium (Tl) and chalcogen elements such as sulfur (S), selenium (Se), and tellurium (Te). These compounds exist in several stoichiometries, including TlX (X = S, Se, Te) and Tl2X3, corresponding to thallium in the +1 and +3 oxidation states, respectively.

In the solid state, thallium chalcogenides exhibit a range of crystal structures, including chain-like, layered, and three-dimensional frameworks. They are typically semiconductors with narrow to moderate band gaps and significant ionic character, and their properties depend on the chalcogen and the exact composition.

Synthesis is commonly accomplished via direct reaction of thallium with the chalcogen at elevated temperatures, or by sulfidation/selenization of thallium-containing precursors. Some phases are sensitive to air and moisture or show polymorphism; thallium compounds are highly toxic, so handling requires appropriate safety precautions.

Research on Tl chalcogenides covers fundamental solid-state chemistry and physics, as well as potential applications in electronics, optoelectronics, and thermoelectrics. Their electronic structures can be exploited in sensor, photoconductive, or nonlinear optical contexts, though practical use is limited by toxicity and stability concerns. Notable examples include Tl2S, Tl2Se, Tl2Te, as well as related thallium(III) chalcogenides Tl2X3 reported for X = S, Se, Te.