Structure and conduction properties of new series of 1-d conductors with mixed inorganic anions, (TTF)(X)x(Cl)y-(X=ClO4, BF4, SCN)-the effect of the anion disorder upon the conducting chains

A new series of 1-d TTF conductors of the non-stoichiometric composition of mixed inorganic anions was found to be isostructural to each other having a space group P42/mnm, tetragonal lattice and disordered anion structure with diverse stoichiometry. TTF radical forms stable 1-d conducting stacking column of the repeating distances of 3.595Å–3.608Å and shows d.c. conductivity of 7–72S/cm. All the conduction study with variable temperature showed metal-insulator transition around 250K and below this temperature it was found to be well fitted to the Mottʹs 1-d variable range hopping model. The effect of the anion disorder and mixing upon the conducting chain is discussed in relation to the localization of the Bloch state perturbed by the random potentials of the anions.