Potassium TCNQ is an stoichiometric organic based salt that undergoes a spin Peierls (SP) transition at approximately 390 K. Much research has been conducted on this system in previous decades, including our previous µSR experiments. Recently we have synthesised the fluorinated derivative, KTCNQF4, where on substitution of the protons the temperature at which a SP transition is observed is reduced to 150 K. Recent muon experiments on the system have shown that the muons are sensitive to the transition where a critical slowing down of spins is seen on the opening of a spin gap as T decreases in both the H4 and F4 samples. However there is a remarkable difference between the two where a significant missing fraction is observed in the protio sample below Tsp where a muonium radical state may exist, however in the F4 sample a muon-F entangled state is observed but no missing fraction.