chemistry

Lead styphnate

Lead styphnate is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lead styphnate rather than just read about it. In short: 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.

Key takeaways

Lead styphnate belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lead styphnate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lead styphnate from memory before moving on to harder problems.

Reference excerpt

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. 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. 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. 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 Lead styphnate (or, as it was then called, trinitro-orcinate) was discovered along with many other trinitroresorcinate 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.

{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.

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 for military and commercial applications. It serves as a primary explosive 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. In order to replace traditional mercury fulminate in cap compositions, lead styphnate is sensitised by the addition of a small quantity of tetrazine. Typical cap compositions would also contain scintillating compounds like antimony sulphide and calcum silicide.

References

External links National Pollutant Inventory - Lead and Lead Compounds Fact Sheet

Illustrations

Worked examples

Example 1 — a first encounter with Lead styphnate

Start with the simplest possible case. Write down what Lead styphnate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lead styphnate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lead styphnate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lead styphnate

In research: Lead styphnate appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lead styphnate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lead styphnate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Explosive chemicals, Lead(II) compounds, Nitrophenol derivatives, so understanding it makes those chapters shorter.
In everyday life: Look for Lead styphnate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Lead styphnate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lead styphnate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lead styphnate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lead styphnate in simple terms?

Why does Lead styphnate matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lead styphnate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lead styphnate.