The New Semiconducting Magnetic Charge Transfer Salt (BEDT-TTF)4 • H2O • Fe(C2O4)3 • C6H5NO2: Crystal Structure and Physical Properties

Abstract

The structure, resistivity and ESR of a new molecular charge transfer salt β-(salt (BEDT-TTF)4 • H2O • Fe(C2O4)3 • C6H5NO2 (BEDT-TTF = bis (ethylenedithio)tetrathiofulvalene) are studied. The structure of the salt consists of successive layers of BEDT-TTF which are packed according to β-type and layers of approximately hexagonal geometry containing alternating H2O and Fe(C2O4)3 3−, with C6H5NO2 lying within the hexagonal cavity. Its main crystallographic parameters are found to be: M = 1999.6(1), a = 10.31(8), b = 20.14(8), c = 35.34(4) Å, β = 92.21(9)° V = 7342.0(5) Å3, space group C2/c; Z = 4. The conductivity of this salt at room temperature is l0 Scm−1 and shows semiconducting behaviour from 20 to 300K. The ESR line width is found to be 38.1 (300 K), which is substantially wider than a typical line width for BEDT-TTF based radical cation salts of the β-type, indicating a two-dimensional character. The comparison of crystal structure and properties of the title compound with other salts of this family (BEDT-TTF)4 • A • Fe(C2O4)3 • C6H5NO2, where A = H2O, K+ or NH4 +, is also carried out.