Lead styphnate hydrate

Tompkins and Young [50] examined the thermal decomposition of barium styphnate and found it to be similar to that of lead styphnate hydrate (Fig. 54). 

It was not until 1954 that preparation of the pure compound, normal lead styphnate hydrate, was accomplished. Up to this time the impure salt (-93%) was used extensively. 

Performance tests consisted of loading DBX-1 as a transfer charge in U.S. Army M55 stab detonators. Standard M55 detonators consist of three separate explosive layers, pressed sequentially into a metal detonator cup as shown in Figure 6. The first layer is 15 mg of the stab initiation mix (NOL-130) it is a combination of lead azide, lead styphnate, barium nitrate, antimony sulfide, and tetrazene [l-(5-tetrazolyl)-3-guanyltetra-zene hydrate], pressed at 70,000 psi. The second layer is 51 mg of transfer charge, lead azide, pressed at 10,000 psi. Lastly, the third layer is 19 mg of output charge, RDX, pressed at 15,000 psi. 

Normal lead styphnate (LS) [Structure (2.10)] was first reported by Von Herze in 1914, although its basic salt, that is, basic LS was prepared by Griess [7] way back in 1874, by the reaction of acidified magnesium styphnate with lead nitrate/acetate in hot aqueous solution. It is precipitated as mono hydrate and consists of reddish-brown rhombic crystals. It is filtered off, washed with water, sieved through a stainless steel sieve and dried. Like other initiatory explosives, it is kept in wet conditions until used. 

Flo. 53. Loss of water of crystallization by the neutral salt of lead styphnate at various temperatures 1—145°C,2—135°C,5— 115°C, 4—hydration curve at 30°C, according... 

Lead picrate is considered highly sensitive to mechanical impact and thermal stimuli [6]. The anhydride is more sensitive to mechanical stimuli than the hydrates. Impact sensitivity of anhydride is significantly higher than the sensitivity of mercury fulminate (4 cm/0.5 kg vs. 24 cm for MF) [7,8]. Handling of lead picrate anhydride represents the same level of risk as handling of lead styphnate. The ignition temperature is 281 °C (explosion takes place instantaneously or within 1 s) [7]. The formation of lead picrate by reaction of tetryl (which decomposes to picric acid) with lead azide is reported as a possible reason for the higher sensitivity of this mixture compared to pure LA [6]. 

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