The actual molecular formula is C9H12N6: Johnson, Rinehart, J. Am. Chem. Soc. 46, 768, 1653 (1924). Prepd by the action of formaldehyde on a mixture of ammonium chloride, potassium cyanide and acetic acid: Adams, Langley, Org. Synth. coll. vol. I (2nd ed., 1941) p 355.