Preparation, stability regions, and properties of M2TeI6 (M = Rb, Cs, Tl) crystals

The stability regions of Rb(2)Tel(6), Cs2TeI6, and Tl2TeI6 were mapped out using quantitative thermal analysis and microbardness measurements on annealed and quenched samples. The congruently melting compositions of the three compounds were shown to coincide with their stoichiometric compositions. A procedure was developed for growing Rb2TeI6, Cs2TeI6, and TI2TeI6 single crystals, and some properties of the grown crystals were investigated.