Lead styphnate

Lead styphnate
Names
Preferred IUPAC name
Lead(II) 2,4,6-trinitrobenzene-1,3-bis(olate)
Other names
Lead 2,4,6-trinitrobenzene-1,3-diolate
Lead 2,4,6-trinitro-m-phenylene dioxide
1,3-Benzenediol, 2,4,6-trinitro-, lead(2+) salt (1:1)
Lead tricinate
Lead trinitroresorcinate
Tricinat[1]
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.035.703
EC Number 239-290-0
UN number 0130
Properties
C6HN3O8Pb
Molar mass 450.288 g/mol
Density 3.06 to 3.1 g cm−3
Explosive data
Shock sensitivity High
Friction sensitivity High
Detonation velocity 5200 m/s
Hazards
Safety data sheet Oxford MSDS
Harmful (X), Dangerous for the environment (N), Explosive (E)
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 4: Very short exposure could cause death or major residual injury. E.g., VX gasReactivity code 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g., fluorineSpecial hazards (white): no codeNFPA 704 four-colored diamond
0
4
3
330 °C (626 °F; 603 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Lead styphnate (lead 2,4,6-trinitroresorcinate, C6HN3O8Pb ), whose name is derived from styphnic acid, is an explosive used as a component in primer and detonator mixtures for less sensitive secondary explosives. Lead styphnate is only slightly soluble in water and methanol[2] Samples of lead styphnate vary in color from yellow to gold, orange, reddish-brown, to brown. Lead styphnate is known in various polymorphs, hydrates, and basic salts. Normal lead styphnate monohydrate, monobasic lead styphnate, tribasic lead styphnate dihydrate, and pentabasic lead styphnate dehydrate as well as α, β polymorphs of lead styphnate exist.

Two forms of lead styphnate are six-sided monohydrate crystals and small rectangular crystals. Lead styphnate is particularly sensitive to fire and the discharge of static electricity. When dry, it can readily detonate by static discharges from the human body. The longer and narrower the crystals, the more susceptible lead styphnate is to static electricity. Lead styphnate does not react with metals and is less sensitive to shock and friction than mercury fulminate or lead azide. It is stable in storage, even at elevated temperatures. As with other lead-containing compounds, lead styphnate is toxic owing to heavy metal poisoning.

Preparation

Although never substantiated, lead styphnate may have been discovered by Peter Griess (of Griess test fame) in 1874. In 1919, Edmund Herz first established a preparation of anhydrous normal lead styphnate by the reaction of magnesium styphnate with lead acetate in the presence of nitric acid.[3][4]

{C6N3O8}MgH2O + Pb(CH3CO2)2 → {C6N3O8}PbH2O + Mg(CH3CO2)2

Structure

Normal lead styphnate exists as α and β polymorphs, both being monoclinic crystals. The lead centres are seven-coordinate and are bridged via oxygen bridges. The water molecule is coordinated to the metal and is also hydrogen-bonded to the anion. Many of the Pb-O distances are short, indicating some degree of covalency. The styphnate ions lie in approximately parallel planes linked by Pb atoms.[5][6]

Properties

Lead styphnate's heat of formation is -835 kJ mol-1. The loss of water leads to the formation of a sensitive anhydrous material with a density of 2.9 g cm−3. The variation of colors remains unexplained.[7] Lead styphnate has a detonation velocity of 5.2 km/s and an explosion temperature of 265-280 °C after five seconds.[8]

Applications

Lead styphnate is mainly used in small arm ammunition for military and commercial applications. It serves as a primary explosive with gunpowder, which will not ignite upon a simple impact.[9] Lead styphnate is also used as primer in microthrusters for small satellite stationkeeping.[10]

References

  1. ↑ ECHA, European Chemicals Agency "Archived copy" (PDF). Archived from the original (PDF) on 2014-10-22. Retrieved 2014-10-17.
  2. ↑ Jacques Boileau, Claude Fauquignon, Bernard Hueber and Hans H. Meyer "Explosives" in Ullmann's Encyclopedia of Industrial Chemistry 2009, Wiley-VCH, Weinheim. doi:10.1002/14356007.a10_143.pub2
  3. ↑ J.R. Payne (1994). "Thermochmistry of lead styphnate". Thermochimica Acta. 242: 13–21. doi:10.1016/0040-6031(94)85003-8.
  4. ↑ Jacques Boileau; Claude Fauquignon; Bernard Hueber; Hans H. Meyer (2009). "Explosives". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a10_143.pub2.
  5. ↑ Pierce-Butler, M.A. (1984). "The structure of the lead salt of 2,4,6-trinitro-1,3-benzenediol monohydrate (alpha-polymorph)". Acta Crystallogr. 40: 63–65. doi:10.1107/S0108270184003036.
  6. ↑ Pierce-Butler, M.A. (1982). "Structures of the barium salt of 2,4,6-trinitro-1,3-benzenediol monohydrate and the isomorphous lead salt (beta-polymorph)". Acta Crystallogr. 38: 3100–3104. doi:10.1107/S0567740882010966.
  7. ↑ Robert Matyáš; Ji í Pachman (2013). "Primary Explosives". Springer Science & Business Media. doi:10.1007/978-3-642-28436-6.
  8. ↑ Hyman Henkin; Russell McGill (1952). "Rates of Explosive Decomposition of Explosives. Experimental and Theoretical Kinetic Study as a Function of Temperature". Ind. Eng. Chem. 44: 1391–1395. doi:10.1021/ie50510a054.
  9. ↑ Gray, Theodore (2009). "Flash Bang". Popular Science.
  10. ↑ Daniel W. Youngner; et al. (2000). "MEMS Mega-pixel Micro-thruster Arrays for Small Satellite Stationkeeping". Honeywell Technology 14th Annual/USU Conference on Small Satellites.
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