Structures and electrical properties of β- and θ-(BTM-TTP)2SbF6

Two kinds of (BTM-TTP)(2)SbF6 salts, where BTM-TTP is 2-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-5-(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, have been prepared. X-ray structure analyses have revealed that needle-like and plate-like crystals have the so-called beta- and theta-type arrays of the donors, respectively. The beta-type salt exhibits metallic conducting behavior down to 5 K, while the theta-type salt is a semiconductor even at room temperature.