2,2,3,3,4,4,5,5-Octafluorohexanedinitrile376-53-4100 % similar 2,2,3,3,4,4,4-Heptafluorobutanenitrile375-00-874 % similar Trifluoroacetonitrile353-85-542 % similar Octafluorocyclobutane115-25-331 % similar Perfluorocyclohexane355-68-031 % similar