Crystal structure and magnetic properties of a thiazyl organic ferromagnet, BBDTA • GaCl4 with Tc=7.0 K

Three polymorphs, labeled alpha (plates), beta (needles), and gamma (blocks), of BBDTA(=benzo[1,2-d:4,5-d']bis[1,3,2]dithiazole).GaCl4 were obtained as a mixture of three polymorphs, by recrystallization at -23 degreesC. The gamma-phase showed the ferromagnetic ordering at 7.0 K. in contrast to diamagnetic properties of the alpha- and beta-phases. The crystal structure of the gamma-phase exhibited a minimal overlap between the singly occupied molecular orbitals of neighboring molecules, in spite of short interatomic S...N distances. (C) 2004 Elsevier B.V. All rights reserved.