Structure of bis(ethylenedithio)tetrathiafulvalenium dichlorocyanoselenate (2:1), (BEDT-TTF){sub 2}Cl{sub 2}SeCN

The electron donor molecule BEDT-TTF has yielded approximately 50 superconductors to date. In addition, numerous other salts with a variety of electrical and magnetic properties have been discovered. Recently, the authors reported a semiconducting salt of BEDT-TTF with the novel T-shaped anion Br{sub 2}SeCN{sup {minus}2}. The crystallographic analysis of that salt revealed a near-centrosymmetric triclinic structure, except for the symmetry-breaking anion. On the basis of a Hamilton R-value test, the non-centrosymmetric space group P1 with ordered anions was preferred over centrosymmetric P{bar 1} with disordered anions. In this paper, the authors present the synthesis and crystal structure of the isostructural chlorine-analogue salt (BEDT-TTF){sub 2}Cl{sub 2}SeCN