STRUCTURAL STUDY OF THE 2 PHASES OF TETRAKIS(METHYLSELENO)-TETRATHIAFULVALENE (TSEC1-TTF)

The crystal structure of the low-melting point phase (L-phase) of a single component organic semiconductor, TSeC1-TTF, is determined and compared with that of the high-melting point phase (H-phase). The intracolumnar overlap mode and the calculated intermolecular overlap integrals are slightly larger in the L-phase, to which is ascribed the low resistivity of the L-phase. The L-phase, however, does not have two-dimensional networks of intercolumnar Se...Se contacts, which exist in the H-phase). This may be associated with the difference of the melting points.