N + ▁t etra eth yl am mon ium , ▁( C 2 H 5 ) 4 N + ▁t etra pro py lam mon ium , ▁( C 3 H 8 ) 4 N +) ▁t etra but yl am mon ium , ▁( C 4 H 1 0 ) 4 N + ▁or ▁abbre vi ated ▁Bu 4 4 N + ▁trim eth yl ▁am mon ium ▁comp ounds , ▁( CH 3 ) 3 R N + ▁di de cy ld im eth yl am mon ium , ▁( C 1 0 H 2 1 ) 2 ( CH 3 ) 2 N + ▁pent am eth yl h yd raz in ium , ▁N ( CH 3 ) 2 N ( CH 3 ) ▁t etra flu oro am mon ium , ▁N F ▁qu atern ary ▁ph os phon ium ▁c ations , ▁R 4 P + ▁or ▁PR ▁t et raph en yl ph os phon ium , ▁( C 6 H 5 ) 4 P + ▁secondary ▁sul fon ium ▁c ations , ▁R 2 SH + ▁( pro ton ated ▁sul f ides ) ▁dim eth yl s ulf on ium , ▁( CH 3 ) 2 SH + ▁( pro ton ated ▁dim eth yl ▁sul f ide ) ▁t ert i ary ▁sul fon ium ▁c ations , ▁R 3 S + ▁trim eth yl s ulf on ium , ▁( CH 3 ) 3 S + ▁secondary ▁flu or on ium ▁c