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

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 group P2₁) of each crystal grown of κ-(BEDT-TTF)₂Cu(NCS)₂ was 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.