My apologises. I've just checked a textbook and in mass spectrometry CH4 loses an electron to form the radical .CH4+ this reacts with CH4 to form the CH3 radical and CH5+ This is unusual as it only has eight electrons but still forms 5 bonds. These are distributed between the five bonds (hence the + charge) and the structure is thought to be trigonal bipyramidal. This structure has not been determined as it's too unstable. It's merely proposed from theoretical calculation.
CH5+ is an unstable compound which functions as a powerful acid and can protonate pretty much everything when it protonates something a proton is removed but no electrons.