A new BEDT-TTF-based charge-transfer salt, (BEDT-TTF)₂C₃H₅SO₃·H₂O (BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene, C₃H₅SO₃^-=allylsulfonate), has been prepared by oxidative electro-crystallization at a constant current of 1.5 μA. The single crystal structure was determined by four-circle X-ray diffraction method. The crystal belongs to orthorhombic system, Pma2 space group with the unit cell parameters of a=3.2772(3) nm, b=0.79604(7) nm, c=0.66868(7) nm, V=1.7445(3) nm³. In the crystal of the title compound, the BEDT-TTF cations adopt an α′-type packing pattern and organic counter anions form infinite chains by hydrogen bonds along c-axis. The room-temperature conductivity of the salt is 0.0489 Ω^-1·m^-1. The resistivity-temperature curve demonstrates that it is a typical semiconductor with an activation of 0.319 eV.

Key words: BEDT-TTF, electrocrystallization, crystal structure, semiconductor