A NEW STABLE ORGANIC METAL IN THE WELL-KNOWN FAMILY OF RADICAL-CATIONALPHA-SALTS - ALPHA-(BETS)(2)TLHG(SECN)(4) - SYNTHESIS, STRUCTURE ANDPROPERTIES

The stable organic metal alpha-(BETS)(2)TIHg(SeCN)(4) has been obtaine d by means of electrochemical oxidation of bis(ethylenedithio)tetrasel enafulvalene (BETS) in 1,1,2-trichloroethane (TCE) with the addition o f absolute ethanol in the presence of an electrolyte consisting of 18- crown-6, TISeCN and Hg(SeCN)(2). The salt is isostructural with the ET -based salt with the same anion and ET and BETS salts with KHg(SCN)(4) as well. The number of the side-by-side Se ... Se, Se ... S and S ... S contacts in each radical cation layer was twice that in comparison with the corresponding ET salt. Reflectivity spectra and magnetoresist ance were studied. The Shubnikov-de Haas effect and angular oscillatio ns of the magnetoresistance were observed. Optical and transport prope rties of alpha-(BETS)(2)TIHg(SeCN)(4) were compared with those of the analogous ET salt.