The crystal structure of the 1:1 radical cation–radical anion salt of 2,2'-bis-l,3-dithiole (TTF) and 7,7,8,8-tetracyanoquinodimethane (TCNQ)

The salt of the radical cation of 2,2'-bis-l,3-dithiole (TTF) and the radical anion of 7,7,8,8-tetracyanoquinodimethane (TCNQ), C18HaN4S4, crystallizes in the monoclinic system, space group P2~/c, with cell constants: a= 12.298 (6), b=3"819 (2), c= 18"468 (8) /~, fl= 104"46 (4) °, Z=2, Dm= 1"62 (1) and Dc=1"615 g cm -3. Intensities for 1373 independent reflections were collected on an automated diffractometer. The structure was solved by standard heavy-atom methods and has been refined by fullmatrix least-squares calculations to an R value of 0"044. The TTF radical cations and the TCNQ radical anions form homologous columnar stacks with interplanar spacings of 3.47 and 3.17 A, respectively. The dihedral angle between the least-squares planes of the cations and the anions is 58.5 ° and is approximately bisected by [010].