Phase relations in the systems A2TeI6-Tl2TeI6 (A = K, Rb, Cs) and A2TeBr6-A2TeI6 (A = K, Rb, Cs, Tl(I))

Abstract

are studied. System VI contains a continuous series of solid solutions, while the other systems have eutectic phase relations with rather broad solid-solution ranges. The relationship between the ionic radii of A + and Hal -(Hal = Br, I) is shown to play a key role in determining the structure type of the A 2 TeHal 6 compounds and the phase relations in the systems studied.

Rotational phase transitions in antifluorite-type osmate and iridate compounds

“…Note however that for compounds with Me = Te, T S follows also a linear tendency against t suggesting an effective ionic radius of ≈0.67 Å (instead of 0.97 Å) for Te 4+ in this material class. The Te-X bond distances d calc,n for 4 Structural information reported in the main text: K 2 WCl 6 [44]; K 2 SeBr 6 [45,46]; K 2 PtI 6 [47]; K 2 PtBr 6 [48,49]; K 2 PtCl 6 [50]; K 2 ReBr 6 [48]; K 2 SnBr 6 [51]; K 2 TeBr 6 [40]; K 2 TeI 6 [52,53]; K 2 TcCl 6 [54]; K 2 TaCl 6 [55]; K 2 ReI 6 [56]; K 2 NbCl 6 [57]; (NH 4 ) 2 PtI 6 [58,59]; (NH 4 ) 2 PtBr 6 [58,60,61]; (NH 4 ) 2 RuCl 6 [60];(NH 4 ) 2 TeCl 6 [39,62,63] (transition to a trigonal space group, octahedra rotation angle around (111)c); (NH 4 ) 2 TeBr 6 [64,65]; (NH 4 ) 2 TeI 6 [66,67]; (NH 4 ) 2 ReI 6 [68,69]; (NH 4 ) 2 SnBr 6 [70][71][72]; (NH 4 ) 2 SnBr 6 [73,74]; (NH 4 ) 2 PbCl 6 [75] (transition to a trigonal space group, octahedra rotation angle around (111)c); Rb 2 PtI 6 [58,61]; Rb 2 TeBr 6 [76]; Rb 2 TeI 6 [77]; Rb 2 TaCl 6…”

The study of optoelectronic and thermoelectric properties of Tl 2 PdX 6 (X = Cl, Br, I) for energy harvesting

“…Recently, the Rb 2 TeX 6 (X = Cl, Br, and I) is also studied systematically for optoelectronics. The crystal structure of these compounds constitutes [TeX 6 ] 2− anions surrounded by Rb +1 cations 22,23 . Tl loses its toxic behavior in compounds formation because toxicity depends upon the oxidation‐reduction process.…”

Halide Perovskite-Derived Compounds Rb2TeX6 (X = Cl, Br, and I): Electronic Structure of the Ground and First Excited States

“…On binding cations, they form structures with densely packed layers. Crystals with [TeCl 6 ] 2– and [TeBr 6 ] 2– anions have strong luminescent properties, ,,, whereas those with [TeI 6 ] 2– anions show polymorphism and phase transitions. − An interesting feature of these crystals is that the probability of transitions to the excited states depends mainly on the local environment of the s 2 -ion, i.e. the halogen atom.…”