beta CO-(ET)(2)I-3: Non-electrochemical synthesis and structural and physical properties of anorganic superconductor with 7.1 K<=T-c<=7.9 K

Synthesis of the superconducting radical cation salt beta(CO)-(ET)(2)I-3 obtained by the direct oxidation of either hydrogenated or deuterated bis(ethylenedithio)tetrathiafulvalene (ET) with a stoichiometric amount of iodine is reported. The Structural and physical properties of the resulting compounds are presented and compared with those of other (ET)(2)I-3 phases. beta(CO)-(ET)(2)I-3 is found to have very similar superconducting properties to those of alpha(t)-(ET)(2)I-3 and the question is raised as to whether they are actually distinct phases.