Reported here is the first observation of anα-Muonium-substituted methyl radical. The key to the success of this experiment was the use of a more stable precursor, trimethylsilyldiazomethane, in lieu of the prototypical diazomethane. The radical, CHMuSi(CH3)3 was observed by TF-μSR, with Aμ=187.6(2) MHz. This result is compared to literature values for the proton analogue and the isotope effect is discussed.
