|Vernon W. Hughes particle physics
An electron, having a negative charge, can bond with a positively charged particle such as an antimuon, forming an exotic light isotope of hydrogen that can, for 2.2 microseconds, be studied with muon spin spectroscopy, and form chemical compounds such as muonium chloride and sodium muonide.
Muonium is not to be confused with true muonium, which is a muon-antimuon pair, or with a muonic atom in which a muonium replaces an electron. The muon was first thought to be a meson and called the “mu meson.” Now, unlike the pion, the meson is known to be a lepton.
A mayfly leads a short lifetime though any muonium would envy the mayfly if it were animate and able to envy.