Lead styphnate

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Lead styphnate
Bleistyphnat.png
Identifiers
CAS number 15245-44-0 YesY
PubChem 61789
ChemSpider 55674 N
EC-number 239-290-0
UN number 0130
Jmol-3D images Image 1
Properties
Molecular formula 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
MSDS Oxford MSDS
EU classification Harmful (X), Dangerous for the environment (N), Explosive (E)
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity 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., fluorine Special hazards (white): no codeNFPA 704 four-colored diamond
Autoignition temperature 330 °C (626 °F; 603 K)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
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 methyl alcohol[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[edit]

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[edit]

Normal lead styphnate exists as α and β polymorphs, both being monoclinic crystals. The lead centres are seven0coordinate 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[edit]

Its heat of formation is -835 kJ mol-1. The loss of water leads to the formation of a sensitive anhydrous maaterial 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[edit]

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[edit]

  1. ^ ECHA, European Chemicals Agency http://echa.europa.eu/documents/10162/13638/svhc_supdoc_lead_styphnate_en.pdf
  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,. doi:10.1016/0040-6031(94)85003-8. 
  4. ^ Jacques Boileau, Claude Fauquignon, Bernard Hueber and 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. Cryst. 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. Cryst. 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. doi:10.1021/ie50510a054. 
  9. ^ Gray, Theodore (2009). [hhttp://www.periodictable.com/PopSci/2009/10/01/index.html "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. 

External links[edit]