Molecular and crystal structures of 6-trifluoromethyl-5-perfluoroethyl-7,7-difluoro-2,3-dihydro-1,4-dioxepin-5,6-trifluoromethyl-5-perfluoroethyl-2,3-dihydro-1,4-dioxepin-5-one-7 and 2-methyl-6-trifluoromethyl-5-perfluoroethyl-2,3-dihydro-1,4-dioxepin-5-one-7 |