Carbocations

thumb|120px|The tert-butyl cation is a relatively stable carbenium ion.

chemical compound

circular ion

Pararosaniline, pararosaniline free base, Basic Red 9, or C.I. 42500 is an organic compound with the formula . It is the free base form of pararosaniline hydrochloride, , a magenta solid with a variety of uses as a dye. It is one of the four components of basic fuchsine. It is structurally related to other triarylmethane dyes called methyl violets (e.g. crystal violet) which feature methyl groups on nitrogen.

any cation that has a pentavalent carbon atom

class of ions

In organic chemistry, methenium (also called methylium, carbenium, methyl cation, or protonated methylene) is a cation with the formula . It can be viewed as a methylene radical (:) with an added proton (), or as a methyl radical (•) with one electron removed. It is a carbocation and an enium ion, making it the simplest of the carbenium ions.

class of ions

chemical compound

In chemistry, methanium is a complex positive ion with formula (metastable transitional form, a carbon atom covalently bonded to five hydrogen atoms) or (fluxional form, namely a molecule with one carbon atom covalently bonded to three hydrogen atoms and one dihydrogen molecule), bearing a +1 electric charge. It is a superacid and one of the onium ions, indeed the simplest carbonium ion.

chemical compound

thumb|200px|right|Ethenium () In chemistry, ethenium, protonated ethylene or ethyl cation is a positive ion with the formula . It can be viewed as a molecule of ethylene () with one added proton (), or a molecule of ethane () minus one hydride ion (). It is a carbocation; more specifically, a nonclassical carbocation.