Structure and magnetotransport properties of the new quasi-two-dimensional molecular metal β"-(BEDT-TTF)4H3O[Fe(C2O4)3] • C6H4Cl2

The beta"-(BEDT-TTF)(4)A(I)[M-III(C2O(4))3] center dot G (A(I)= NH4+, H3O+, K+, Rb+; M-III = Fe, Cr; G = "guest" solvent molecule) family of layered molecular conductors with magnetic metal oxalate anions exhibits a pronounced dependence of the conducting properties on the type of neutral solvent molecules introduced into the complex anion layer. A new organic dichlorobenzene (C6H4Cl2)-containing conductor of this family, namely, beta"-(BEDT-TTF)(4)H3O[Fe(C2O4)(3)] center dot C6H4Cl2, is synthesized. The structure of the synthesized single crystals studied by X-ray diffraction is characterized by the following parameters: a = 10.421(1) angstrom, b = 19.991(2) angstrom, c = 35.441(3) angstrom, beta = 92.87(1)degrees, V = 7374(1) angstrom(3), space group C2/c, and Z = 4. In the temperature range 0.5-300 K, the conductivity of the crystals is metallic without changing into a superconducting state. The magnetotransport properties of the crystals are examined in magnetic fields up to 17 T at T = 0.5 K. In fields higher than 10 T, Shubnikov-de Haas oscillations are detected, and the Fourier spectrum of these oscillations contains two frequencies with maximum amplitudes of about 80 and 375 T. The experimental results are compared with the related data obtained for other phases of this family. The possible structural mechanisms of the effect of a guest solvent molecule on the transport properties of the beta"-(BEDT-TTF)(4)A(I)[M-III(C2O4)(3)] center dot G crystals are analyzed.