2-Chloro-1,3-dimethylimidazolidium tetrafluoroborate153433-26-2100 % similar 1,3-Dimethyl-2-imidazolidinethione13461-16-033 % similar 1,3-Dimethyl-2-imidazolidinone80-73-933 % similar 1,3-Dimethyl-2-fluoroimidazolium hexafluorophosphate164298-27-531 % similar