ros yl , ▁N ≡ S + ▁ ▁Double ▁on ium ▁dic ations ▁hyd raz ined i ium ▁or ▁hyd raz in ium ( 2 +) ▁dic ation , ▁+ H 3 NN H ▁( d ou b ly ▁pro ton ated ▁hyd raz ine ) ▁dia zen edi ium ▁c ation , ▁+ H 2 N = N H ▁( d ou b ly ▁pro ton ated ▁dia z ene ) ▁dia z yn edi ium ▁c ation , ▁+ H N ≡ N H + ▁( d ou b ly ▁pro ton ated ▁[ di ] nit ro gen ) ▁ ▁En ium ▁c ations ▁The ▁extra ▁bond ▁is ▁added ▁to ▁a ▁less - common ▁parent ▁hyd ride , ▁a ▁car b ene ▁analog , ▁typically ▁named ▁- ene ▁or ▁- yl ene , ▁which ▁is ▁neutral ▁with ▁ 2 ▁fewer ▁b onds ▁than ▁the ▁more - common ▁hyd ride , ▁typically ▁named ▁- ane ▁or ▁- ine . ▁b oren ium ▁c ations , ▁ ▁( pro ton ated ▁b ory len es ▁a . k . a . ▁bor any l iden es ) ▁car ben ium ▁c ations , ▁ ▁( pro ton ated ▁car ben es , ▁have ▁a ▁tri val ent ▁carbon ▁atom ▁with ▁a ▁+ 1 ▁charge ) ▁m eth enium ▁c ation , ▁ ▁( pro ton ated ▁m eth yl ene ) ▁s ily li um ▁c ations , ▁ ▁( pro ton ated ▁s ily len es ) ▁nit ren ium ▁c