1,2-Bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene;1,2-Bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene (purified by sublimation);3-[3,3,4,4,5,5-hexafluoro-2-(2-methyl-1-benzothiophen-3-yl)cyclopenten-1-yl]-2-methyl-1-benzothiophene;1,2-bis(2-methyl-3-benzothienyl)perfluorocyclopentene