When the CH3N2+ (methyldiazonium) cation loses a nitrogen molecule, it forms the CH3+ (methyl) cation. This reaction is known as deamination and is a common process in organic chemistry. The loss of the neutral nitrogen molecule results in the formation of a carbocation, which is a positively charged carbon atom. Carbocations are highly reactive and can undergo various reactions, including rearrangements, additions, and eliminations.