Enantiomorph identification and stacking faults in κ-(BEDT-TTF)2Cu(NCS)2by convergent-beam electron diffraction

Abstract

The convergent-beam electron diffraction (CBED) method proposed recently for enantiomorph identification has been successfully applied to an ambient-pressure superconductor κ-(BEDT-TTF)2Cu(NCS)2[BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene]. Enantiomorph identification (either the left-handed or right-handed form within the space groupP21) of each crystal grown of κ-(BEDT-TTF)2Cu(NCS)2was achieved at ambient temperature without the need to cool the specimens. Enantiomorph identification was possible within the framework of the proposed method only by taking an additional selected-area electron diffraction pattern to eliminate the ambiguity of 180° rotation of the relevant CBED pattern about the incident beam. In the present study, all four specimens investigated exhibit the right-handed form.