1, 1, 3, 3-Tetracyanopropane, 1, was prepared in low yields by a literature method with 2, 2, 4, 4, 6-pentacyanocyclohexenamine, 2, as a major by-product. The products were examined by X-ray crystallography. 1 has an orthorhombic space group, Pbcn (No. 60) with cell dimensions, a= 7.158 (2), b= 10.510 (3), c= 9.733 (2) Å and has four formula units in the unit cell. 2 has a monoclinic cell, P 21/c (No. 14) with cell dimensions a= 14.368 (3), b= 6.626 ( ...