Silver fulminate

Silver fulminate
Names
	IUPAC names Silver carbidooxidonitrate(1−); Silver oxidoazaniumylidynemethane
	Other names Silver fulminate; Silver(I) fulminate ; Argentous fulminate
Identifiers
CAS Number	5610-59-3 ;
3D model (JSmol)	Interactive image ;
ChemSpider	56347 ;
PubChem CID	62585 ;
UNII	5QNF7XT857 ;
CompTox Dashboard (EPA)	DTXSID60971484 ;
	InChI InChI=1S/CNO.Ag/c1-2-3;/q-1;+1 Key: AZPZMMZIYMVPCK-UHFFFAOYSA-N;
	SMILES [C-]#[N+][O-].[Ag+];
Properties
Chemical formula	AgCNO
Molar mass	149.885 g/mol
Density	3.938 g/cm3
Explosive data
Shock sensitivity	Extremely high
Friction sensitivity	Extremely high
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Sensitive high explosive
NFPA 704 (fire diamond)	3 3 4
Autoignition; temperature	170 °C (338 °F; 443 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Last updated January 24, 2024

Silver fulminate (AgCNO) is the highly explosive silver salt of fulminic acid.

Silver fulminate is a primary explosive, but has limited use as such due to its extreme sensitivity to impact, heat, pressure, and electricity. The compound becomes progressively sensitive as it is aggregated, even in small amounts; the touch of a falling feather, the impact of a single water droplet, or a small static discharge are all capable of explosively detonating an unconfined pile of silver fulminate no larger than a dime and no heavier than a few milligrams. Aggregating larger quantities is impossible, due to the compound's tendency to self-detonate under its own weight.

Silver fulminate was first prepared in 1800 by Edward Charles Howard in his research project to prepare a large variety of fulminates. Along with mercury fulminate, it is the only fulminate stable enough for commercial use. Detonators using silver fulminate were used to initiate picric acid in 1885, but since have been used only by the Italian Navy.^[3] The current commercial use has been in producing non-damaging novelty noisemakers as children's toys.

Structure

Ball-and-stick model of the cyclic hexamer in trigonal silver fulminate Silver-fulminate-cyclic-hexamer-from-trigonal-xtal-3D-balls-A.png — Ball-and-stick model of the cyclic hexamer in trigonal silver fulminate

Silver fulminate occurs in two polymorphic forms, an orthorhombic one and a trigonal one with a rhombohedral lattice.^[4] The trigonal polymorph consists of cyclic hexamers, (AgCNO)₆.^[5]

Properties

Fulminates are toxic, about the same as cyanides.^[3] When pure, silver fulminate is chemically stable, not decomposing after years of storage. Like many silver salts, it darkens with light exposure. It is slightly soluble in cold water and can be recrystallized using hot water.^[3]^[6] It can also be recrystallized from a 20% solution of ammonium acetate.^[3] It is not hygroscopic and can explode when moist or under water; it was reported to remain explosive after 37 years under water.^[3] It explodes upon contact with concentrated sulfuric acid or chlorine or bromine, but not when contacting iodine.^[3] It is insoluble in nitric acid, but dissolves in ammonia, alkali chlorides, alkali cyanides, aniline, pyridine, and potassium iodide by forming complexes.^[3] Concentrated hydrochloric acid decomposes it non-explosively with a hissing noise; thiosulfate also decomposes it non-explosively, and can be used for disposal.^[3]

Preparation

This compound can be prepared by pouring a solution of silver nitrate in nitric acid into ethanol, under careful control of the reaction conditions, to avoid an explosion.^[7] The reaction is usually done at 80–90 °C; at 30 °C, the precipitate may not form.^[3] Only tiny amounts of silver fulminate should be prepared at once, as even the weight of the crystals can cause them to self-detonate. Another way to make silver fulminate is to react silver carbonate with ammonia in solution.^{[ citation needed ]}

4 Ag₂CO₃ + 4 NH₃ → 4 AgCNO + 6 H₂O + 4 Ag + O₂

Silver fulminate also forms when nitrogen oxide gas is passed through a solution of silver nitrate in ethanol.^[3]

Silver fulminate can be prepared unintentionally, when an acidic solution of silver nitrate comes in contact with alcohol.^[7] This is a hazard in some formulations of chemically silvering mirrors.

Novelty explosive

Silver fulminate, often in combination with potassium chlorate, is used in trick noise-makers known as "throw-downs", "crackers", "snappers", "whippersnappers", "pop-its", or "bang snaps", a popular type of novelty firework. They contain approximately 200 milligrams of fine gravel coated with a minute quantity (approximately 80 micrograms)^[8] of silver fulminate. When thrown against a hard surface, the impact is sufficient to detonate the tiny quantity of explosive, creating a small salute from the supersonic detonation. Snaps are designed to be incapable of producing damage (even when detonated against skin) due to the buffering effect provided by the much greater mass of the gravel medium. It is also the chemical found in Christmas crackers ^[9] having first been used for that purpose by Tom Smith in 1860. The chemical is painted on one of two narrow strips of card, with abrasive on the second. When the cracker is pulled, the abrasive detonates the silver fulminate.

A fulminate mixture with 10–20% potassium chlorate is cheaper and more brisant than the fulminate alone.^[3]

Silver fulminate and "fulminating silver"

Silver fulminate is often confused with silver nitride, silver azide, or fulminating silver. "Fulminating silver", though always referring to an explosive silver-containing substance, is an ambiguous term. While it may be a synonym of silver fulminate, it may also refer to the nitride or azide, the decomposition product of Tollen's reagent, or an alchemical mixture, which does not contain the fulminate anion.

Related Research Articles

An explosive 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 explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances.

Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N₂, a colorless and odorless diatomic gas. N₂ forms about 78% of Earth's atmosphere, making it the most abundant uncombined element in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth.

<span class="mw-page-title-main">Mercury(II) fulminate</span> Chemical compound

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 formula is identical, has a different atomic arrangement; the cyanate and fulminate anions are isomers.

<span class="mw-page-title-main">Ammonium nitrate</span> Chemical compound with formula NH4NO3

Ammonium nitrate is a chemical compound with the formula NH₄NO₃. It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is predominantly used in agriculture as a high-nitrogen fertilizer.

<span class="mw-page-title-main">Silver nitrate</span> Chemical compound

Silver nitrate is an inorganic compound with chemical formula AgNO^₃. It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called lunar caustic because silver was called luna by ancient alchemists who associated silver with the moon. In solid silver nitrate, the silver ions are three-coordinated in a trigonal planar arrangement.

In chemistry, azide is a linear, polyatomic anion with the formula N−3 and structure ⁻N=N⁺=N⁻. It is the conjugate base of hydrazoic acid HN₃. Organic azides are organic compounds with the formula RN₃, containing the azide functional group. The dominant application of azides is as a propellant in air bags.

<span class="mw-page-title-main">Potassium chlorate</span> Chemical compound

Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO₃. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It is a strong oxidizing agent and its most important application is in safety matches. In other applications it is mostly obsolete and has been replaced by safer alternatives in recent decades. It has been used

Sodium azide is an inorganic compound with the formula NaN₃. This colorless salt is the gas-forming component in some car airbag systems. It is used for the preparation of other azide compounds. It is an ionic substance, is highly soluble in water, and is very acutely poisonous.

<span class="mw-page-title-main">Fulminate</span> Chemical compounds containing an –O–N≡C group

Fulminates are chemical compounds which include the fulminate ion. The fulminate ion is a pseudohalic ion because its charge and reactivity are similar to those of the halogens. Due to the instability of the ion, fulminate salts are friction-sensitive explosives. The best known is mercury(II) fulminate, which has been used as a primary explosive in detonators. Fulminates can be formed from metals, such as silver and mercury, dissolved in nitric acid and reacted with ethanol. The weak single nitrogen-oxygen bond is responsible for their instability. Nitrogen very easily forms a stable triple bond to another nitrogen atom, forming nitrogen gas.

<span class="mw-page-title-main">Ammonium chlorate</span> Chemical compound

Ammonium chlorate is an inorganic compound with the formula NH₄ClO₃.

<span class="mw-page-title-main">Silver perchlorate</span> Chemical compound

Silver perchlorate is the chemical compound with the formula AgClO₄. This white solid forms a monohydrate and is mildly deliquescent. It is a useful source of the Ag⁺ ion, although the presence of perchlorate presents risks. It is used as a catalyst in organic chemistry.

<span class="mw-page-title-main">Silver carbonate</span> Chemical compound

Silver carbonate is the chemical compound with the formula Ag₂CO₃. This salt is yellow but typical samples are grayish due to the presence of elemental silver. It is poorly soluble in water, like most transition metal carbonates.

<span class="mw-page-title-main">Silver azide</span> Chemical compound

Silver azide is the chemical compound with the formula AgN₃. It is a silver(I) salt of hydrazoic acid. It forms a colorless crystals. Like most azides, it is a primary explosive.

The chemical element nitrogen is one of the most abundant elements in the universe and can form many compounds. It can take several oxidation states; but the most common oxidation states are -3 and +3. Nitrogen can form nitride and nitrate ions. It also forms a part of nitric acid and nitrate salts. Nitrogen compounds also have an important role in organic chemistry, as nitrogen is part of proteins, amino acids and adenosine triphosphate.

Silver is a relatively unreactive metal, although it can form several compounds. The common oxidation states of silver are (in order of commonness): +1 (the most stable state; for example, silver nitrate, AgNO₃); +2 (highly oxidising; for example, silver(II) fluoride, AgF₂); and even very rarely +3 (extreme oxidising; for example, potassium tetrafluoroargentate(III), KAgF₄). The +3 state requires very strong oxidising agents to attain, such as fluorine or peroxodisulfate, and some silver(III) compounds react with atmospheric moisture and attack glass. Indeed, silver(III) fluoride is usually obtained by reacting silver or silver monofluoride with the strongest known oxidizing agent, krypton difluoride.

<span class="mw-page-title-main">Potassium fulminate</span> Chemical compound

Potassium fulminate is the potassium salt of the fulminate ion. Its only use, aside from chemical demonstrations, is in the percussion caps for some early rifles. Usually prepared by reacting a potassium amalgam with mercury fulminate, it is much less sensitive due to the ionic bond between potassium and carbon, unlike the weaker covalent bond between mercury and carbon.

Explosophores are functional groups in organic chemistry that give organic compounds explosive properties.

Silver nitride is an explosive chemical compound with symbol Ag₃N. It is a black, metallic-looking solid which is formed when silver oxide or silver nitrate is dissolved in concentrated solutions of ammonia, causing formation of the diammine silver complex which subsequently breaks down to Ag₃N. The standard free energy of the compound is about +315 kJ/mol, making it an endothermic compound which decomposes explosively to metallic silver and nitrogen gas.

Barium perchlorate is a powerful oxidizing agent, with the formula Ba(ClO₄)₂. It is used in the pyrotechnic industry.

Silver chlorite is a chemical compound with the formula AgClO₂. This slightly yellow solid is shock sensitive and has an orthorhombic crystal structure.

References

↑ International Union of Pure and Applied Chemistry (2005). Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005). Cambridge (UK): RSC–IUPAC. ISBN 0-85404-438-8. p. 291. Electronic version.
↑ "Silver fulminate". ChemBase. Retrieved 8 June 2012.^{[ permanent dead link ]}
1 2 3 4 5 6 7 8 9 10 11 Matyas, Robert; Pachman, Jiri (Mar 12, 2013). Primary Explosives. Springer Science & Business Media, 338 pages.
↑ Britton, D.; Dunitz, J. D. (1965). "The Crystal Structure of Silver Fulminate". Acta Crystallographica. 19 (4): 662–668. Bibcode:1965AcCry..19..662B. doi:10.1107/S0365110X6500405X.
↑ Britton, D. (1991). "A Redetermination of the Trigonal Silver Fulminate Structure". Acta Crystallographica C. 47 (12): 2646–2647. Bibcode:1991AcCrC..47.2646B. doi:10.1107/S0108270191008855.
↑ 0.0075 gm at 13 °C, 0.018 gm at 30 °C, and 0.25 gm per 100 gm H₂O at 100 °C
1 2 Collins, P. H.; Holloway, K. J. (1978). "A Reappraisal of silver fulminate as a detonant". Propellants, Explosives, Pyrotechnics. 3 (6): 159–162. doi:10.1002/prep.19780030603.
↑ package disclosure of Alexron Co. Ltd, Hong Kong, Phantom Brand Bang Snaps, (c)2013
↑ Spectrum. "Comment #70". Old Firework Factory Locations. UK Pyrotechnics Society. Retrieved 20 December 2011.