Methanium
（重定向自Methonium）
In chemistry, methanium is a positive ion with formula CH+
5, namely a molecule with one carbon atom bonded to five hydrogen atoms and bearing a +1 electric charge. It is a superacid and one of the onium ions, indeed the simplest carbonium ion.
Methanium can be produced in the laboratory as a rarefied gas or as a dilute species in superacids. It was prepared for the first time in 1950 and published in 1952 by Talrose and Lyubimova. It occurs as an intermediate species in chemical reactions.