High tension detonator

Spalt-versuch, m. Min.) cleavage test, -win- el, m. Cryst.) cleavage angle, -zunder, m. high-tension detonator. 

High tension detonator. An early form of detonator which required a voltage exceeding... 

From a chemical viewpoint, the interior of a crystal and its surface can be looked upon as if they were different individuals, comparable to two modifications of a substance or to a metal which is under mechanical stresses. The phenomenon of stress corrosion reveals that the part under tension differs in its chemical reactivity from the part under compression. Different modifications of silica can have very different reactivities. Therefore, it must be expected that the surface film can affect the apparent stability of a solid. Indeed, the surface structures of some hydrated salts are in equilibrium with the ambient atmosphere and prevent these crystals from losing water (efflorescing), even if the bulk of the crystal has a higher water vapor pressure than the atmosphere. The formation of a fresh highly asymmetrical surface may also cause substances to detonate. 

Ammonium azide is a white crystalline salt, with the following solubilities per 100 ml. of solvent, at 20° water 20 g. methanol 3.3 g. ethanol 1.06 g. ether 0.006 g. benzene 0.003 g. It crystallizes from aqueous solutions in anhydrous form, has a relatively high vapor tension, and sublimes at 133° without melting. It is one of the more stable azides but, when properly initiated, detonates with high velocity. It usually detonates with extreme violence when heated in a sealed tube but not in the open air. 

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