Tetracene

1-Guanyl-4-nitrosoaminoguanyltetrazene[20] , called "tetracene" for short, was first prepared by Hoffmann and Roth. Hoffmann and his co-workers studied its chemical reactions and determined its structure.

Properties:
IUPAC NAME: 1(5-tetrazolyl)-4-guanyl tetrazene hydrate
OTHER NAME: tetrazolyl guanyltetrazene hydrate; tetrazen; tétrazéne
MOLECULAR FORMULA: C2H6N10ˇH2O
MOLAR MASS: 188.15 g/mol
SHOCK SENSITIVITY: high
FRICTION SENSITIVITY: high
EXPLOSIVE VELOCITY: ~4000 m/s

It is formed by the action of nitrous acid on aminoguanidine, or, more exactly, by the interaction of an aminoguanidine salt with sodium nitrite in the absence of free mineral acid.

Tetracene is a colorless or pale yellow, fluffy material which is practical1y insoluble in water, alcohol, ether, benzene, and carbon tetrachloride.
Tetracene forms explosive salts, among which the perchlorate is especial1y interesting. It is soluble in strong hydrochloric acid; ether precipitates the hydrochloride from the solution, and this on treatment with sodium acetate or with ammonia gives tetracene again.
Tetracene is only slightly hygroscopic. It is stable at ordinary temperatures both wet and dry, but is decomposed by boiling water with the evolution of 2N2 per molecule. Tetracene explodes readily from flame without appreciable noise but with the production of much black smoke. Rinkenbach and Burton, who have made an extended study of the explosive properties of tetracene, report that it explodes in 5 seconds at 160° (mercury fulminate 190°) . They found that it is slightly more sensitive to impact than mercury fulminate.
The brisance of tetracene, if it is used alone and is fired by a fuse, is greatest when the explosive is not compressed at all. It appears then that tetracene is more brisant-and presumably explodes with a greater velocity of detonation-when initiated by fulminate or tetryl than when self-initiated by fire.
Tetracene is easily dead-pressed, its self-acceleration is low, and it is not suitable for use alone as an initiating explosive. It is as efficient as fulminate only if it is externally initiated. It is used in detonators either initiated by another primary explosive and functioning as an intermediate booster or mixed with another primary explosive to increase the sensitivity of the latter to flame or heat. A recent patent recommends the use of a mixture of tetracene and lead azide in explosive rivets. Tetracene is used in primer caps where as little as 2% in the composition results in an improved uniformity of percussion sensitivity.