Tautomers and Self-condensations
Containing both a nucleophilic and electrophilic site within the same molecule, cyanamide undergoes various reactions with itself. Cyanamide exists as two tautomers, one with the connectivity NCNH2 and the other with the formula HNCNH ("diimide" tautomer). The NCNH2 form dominates, but in a few reactions (e.g. silylation) the diimide form appears to be important.
Cyanamide dimerizes to give 2-cyanoguanidine (dicyandiamide). This decomposition process is disfavored by acids and is inhibited by low temperatures. The trimer is called melamine.
Read more about this topic: Cyanamide