Concept
Methanium
Related concepts (7)
Carbonium ion
In chemistry, a carbonium ion is any cation that has a pentacoordinated carbon atom. The name carbonium may also be used for the simplest member of the class, properly called methanium (), where the carbon atom is covalently bonded to five hydrogen atoms. The next simplest carbonium ions after methanium have two carbon atoms. Ethynium, or protonated acetylene , and ethenium are usually classified in other families. The ethanium ion has been studied as an extremely rarefied gas by infrared spectroscopy.
Ethanium
In chemistry, ethanium or protonated ethane is a highly reactive positive ion with formula C2H7+. It can be described as a molecule of ethane (C2H6) with one extra proton (hydrogen nucleus), that gives it a +1 electric charge. Ethanium is one of the simplest carbonium ions (after methanium CH5+). It was first detected as a rarefied gas in 1960 by S. Wexler and N. Jesse. It easily dissociates into ethenium C2H5+ and molecular hydrogen H2. Ethanium was first detected by infrared spectroscopy among the ions produced by electrical discharges in rarefied methane or ethane gas.
Methenium
In organic chemistry, methenium (also called methylium, carbenium, methyl cation, or protonated methylene) is a cation with the formula CH3+. It can be viewed as a methylene radical (:CH2) with an added proton (H+), or as a methyl radical (•CH3) with one electron removed. It is a carbocation and an enium ion, making it the simplest of the carbenium ions. Experiments and calculations generally agree that the methenium ion is planar, with threefold symmetry. The carbon atom is a prototypical (and exact) example of sp2 hybridization.
Ethenium
In chemistry, ethenium, protonated ethylene or ethyl cation is a positive ion with the formula C2H5+. It can be viewed as a molecule of ethylene (C2H4) with one added proton (H+), or a molecule of ethane (C2H6) minus one hydride ion (H-). It is a carbocation; more specifically, a nonclassical carbocation. Ethenium has been observed in rarefied gases subjected to radiation. Another preparation method is to react certain proton donors such as H3+, HeH+, N2H+, and N2OH+ with ethane at ambient temperature and pressures below 1 mmHg.
Onium ion
In chemistry, an onium ion is a cation formally obtained by the protonation of mononuclear parent hydride of a pnictogen (group 15 of the periodic table), chalcogen (group 16), or halogen (group 17). The oldest-known onium ion, and the namesake for the class, is ammonium, , the protonated derivative of ammonia, . The name onium is also used for cations that would result from the substitution of hydrogen atoms in those ions by other groups, such as organic groups, or halogens; such as tetraphenylphosphonium, .
Carbocation
A carbocation is an ion with a positively charged carbon atom. Among the simplest examples are the methenium CH3+, methanium CH5+ and vinyl C2H3+ cations. Occasionally, carbocations that bear more than one positively charged carbon atom are also encountered (e.g., ethylene dication C2H42+). Until the early 1970s, all carbocations were called carbonium ions. In the present-day definition given by the IUPAC, a carbocation is any even-electron cation with significant partial positive charge on a carbon atom.
Ammonium
The ammonium cation is a positively charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged (protonated) substituted amines and quaternary ammonium cations (), where one or more hydrogen atoms are replaced by organic or other groups (indicated by R). The ammonium ion is generated when ammonia, a weak base, reacts with Brønsted acids (proton donors): The ammonium ion is mildly acidic, reacting with Brønsted bases to return to the uncharged ammonia molecule: Thus, the treatment of concentrated solutions of ammonium salts with a strong base gives ammonia.