1,3-Dithiole, 2-(1,3-dithiol-2-ylidene)- 143413-93-8 31366-25-3 56243-32-4 56481-75-5 87891-32-5 EINECS 250-593-7 NSC 222862 TTF Tetrathiafulvalene delta-2:2'-Bis(1,3-dithiazole)