Lead styphnate (lead 2,4,6- trinitroresorcinate, C₆HN₃O₈Pb ), whose name is derived from styphnic acid, is an

explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ex ...

used as a component in primer and

detonator A detonator is a device used to make an explosive or explosive device explode. Detonators come in a variety of types, depending on how they are initiated (chemically, mechanically, or electrically) and details of their inner working, which of ...

mixtures for less sensitive secondary explosives. Lead styphnate is only slightly soluble in

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

and

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

. 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. Lead styphnate forms six-sided crystals of the monohydrate and small rectangular crystals. Lead styphnate is particularly sensitive to fire and the discharge of

static electricity Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it can move away by an electric current or electrical discharge. The word "static" is used to differentiate it from electric ...

. Long thin crystals are particularly sensitive. Lead styphnate does not react with other metals and is less sensitive to shock and friction than mercury fulminate or

lead azide Lead(II) azide is an inorganic compound. More so than other azides, it is explosive. It is used in detonators to initiate secondary explosives. In a commercially usable form, it is a white to buff powder. Preparation and handling Lead(II) azi ...

. It is stable in storage, even at elevated temperatures. As with other

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

-containing compounds, lead styphnate is toxic owing to heavy metal poisoning.

Preparation

Lead styphnate (or, as it was then called, trinitro-orcinate) was discovered along with many other thrinitroresorcinate salts by British chemist John Stenhouse in 1871, the synthesis route involving action of trinitroresorcinol on lead acetate. In 1919, Austrian chemist Edmund von 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 Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

. :MgH₂O + Pb(CH₃CO₂)₂ → 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.

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. Lead styphnate has a detonation velocity of 5.2 km/s and an explosion temperature of 265–280 °C after five seconds.

Applications

Lead styphnate is mainly used in small arms

ammunition Ammunition, also known as ammo, is the material fired, scattered, dropped, or detonated from any weapon or weapon system. The term includes both expendable weapons (e.g., bombs, missiles, grenades, land mines), and the component parts of oth ...

for military and commercial applications. It serves as a

primary explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

used in firearms primers, which will ignite upon a simple impact. It is similarly used in blank cartridges for powder-actuated nail guns. Lead styphnate is also used as primer in microthrusters for small satellite stationkeeping.{{cite journal, author=Daniel W. Youngner, title=MEMS Mega-pixel Micro-thruster Arrays for Small Satellite Stationkeeping, journal=Honeywell Technology 14th Annual/USU Conference on Small Satellites, year=2000, url=http://alfven.princeton.edu/publications/youngner-ssc-2000, display-authors=etal, access-date=2016-10-18, archive-date=2021-03-10, archive-url=https://web.archive.org/web/20210310033937/https://alfven.princeton.edu/publications/youngner-ssc-2000, url-status=dead

References

External links

National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
Lead(II) compounds Explosive chemicals Nitrobenzene derivatives Phenolates