Synthesis of TISm 2I 5 by a one-step procedure

Abstract

As part of an effort to improve the one-step method for direct synthesis of TISm 2I 5 from TlI:HgI 2:Sm in 1:2:2 molar ratio mixtures, the TISm 2I 5 formation process has been investigated by differential thermal analysis and X-ray powder diffraction methods. The results indicate that two pathways lead to the formation of TISm 2I 5. The first involves reaction between TlI and samarium at 440–508 K to produce SmI 2, which in turn acts as an intermediate for TISm 2I 5 formation via reaction with TlI. The second pathway involves the intermediate Tl 4HgI 6 from HgI 2 and TlI; this intermediate is converted to the final product, TISm 2I 5. The Tl 4HgI 6 intermediate reacts slowly with samarium in the solid state but more rapidly in the liquid state. The TlI thus serves both as a reactant and a flux and serves to reduce the reaction temperature.