# What is the chemical symbol for Mu-mesic atoms?

Is there a convention for chemical symbols of mu-mesic atoms, at least for ones bound to light atomic nuclei?

There is an official convention for a positive muon being a nucleus, that a positive muon with one electron is muonium ($\mathrm{Mu}$) and a positive muon with two electrons is muonide ($\mathrm{Mu^-}$). See Names for Muonic and Hydrogen Atoms and Their Ions.
For a negative muon replacing an electron in helium, I see both $\mathrm{He\mu}$ and $\mathrm{^{4.1}H}$ in the same paper: Kinetic Isotope Effects for the Reactions of Muonic Helium and Muonium with $\mathrm{H_2}$.