THE 1ST ET SALT WITH A METAL-COMPLEX ANION CONTAINING A SELENOCYANATELIGAND, (ET)2TLHG(SECN)4 - SYNTHESIS, STRUCTURE AND PROPERTIES

Synthesis of the first ET salt with a metal complex anion containing a selenocyanate ligand, alpha-(ET)2TlHg(SeCN)4, and its structure are r eported. The temperature dependence of conductivity and thermopower in various crystallographic directions and the Shubnikov-de Haase oscill ations have been studied. Distinctions of the bond length distribution s in three crystallographically independent ET have been found, which may result in some charge localization in the radical-cation layer. A detailed comparison of the structure and properties of the compound ob tained to its thiocyanate analog has been performed. It has been shown that in the alpha-(ET)2TlHg(SeCN)4 salt there is no low-temperature p hase transition characteristic of the alpha-(ET)2MHg(SCN)4 compounds w ith M = K, Tl and Rb.