Organic metals. van der Waals donor stacking in TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane)

Abstract

The slipped stacking geometry of TTF in TTF-TCNQ and in neutral TTF is shown to be consistent with the close packing of hard spheres having atomic van der Waals radii. Slipped or eclipsed stacking in TTF compounds is suggested to result from a competition between closed shell interactions and those interactions that arise from partially emptying the highest occupied π-molecular orbital. This contrasts with TCNQ stacking in TCNQ salts which has been previously argued to be a consequence of only those interactions that result from filling the π-molecular-orbital affinity level. © 1979 American Institute of Physics.