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

styphnic acid Styphnic acid (from Greek ''stryphnos'' "astringent"Alexander Senning (2006). ), or 2,4,6-trinitro-1,3-benzenediol, is a yellow astringent acid that forms hexagonal crystals. It is used in the manufacture of dyes, pigments, inks, medicines, and ex ...

, 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 expl ...

used as a component in

primer Primer may refer to: Arts, entertainment, and media Films * ''Primer'' (film), a 2004 feature film written and directed by Shane Carruth * ''Primer'' (video), a documentary about the funk band Living Colour Literature * Primer (textbook), a t ...

and

detonator A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electri ...

mixtures for less sensitive

secondary 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 expl ...

s. Lead styphnate is only slightly soluble in

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

and

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

. 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 In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was underst ...

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 or between materials. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is na ...

. 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 Mercury(II) fulminate, or Hg(CNO)2, is a primary explosive. It is highly sensitive to friction, heat and shock and is mainly used as a trigger for other explosives in percussion caps and detonators. Mercury(II) cyanate, though its chemical formu ...

lead azide Lead(II) azide is an inorganic compound. More so than other azides, 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) azide is ...

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

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

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

Preparation

Although never substantiated, lead styphnate may have been discovered by

Peter Griess Johann Peter Griess (6 September 1829 – 30 August 1888) was an industrial chemist and an early pioneer of organic chemistry. Griess was influential in the formation of modern dyes, first formulating the diazotization reaction of arylamines. Li ...

(of

Griess test The Griess test is an analytical chemistry test which detects the presence of nitrite ion in solution. One of its most important uses is the determination of nitrite in drinking water. The Griess diazotization reaction, on which the Griess reage ...

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. :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 (informally ammo) is the material fired, scattered, dropped, or detonated from any weapon or weapon system. Ammunition is both expendable weapons (e.g., bombs, missiles, grenades, land mines) and the component parts of other weap ...

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 expl ...

used in firearms primers, which will ignite upon a simple impact. 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

References

External links

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