Silver fulminate

Silver fulminate
Identifiers
CAS number	[5610-59-3]
PubChem	62585
Properties
Molecular formula	AgCNO
Molar mass	149.885 g mol−1
Explosive data
Shock sensitivity	Very high
Friction sensitivity	Very high
Hazards
Autoignition temperature	170 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references

Silver fulminate (AgCNO) is an explosive ionic compound of silver and the fulminate anion.

Silver fulminate is a primary explosive that has very little practical value due to its extreme sensitivity. The impact of a single water droplet has been known to detonate several milligrams of silver fulminate. Even small amounts of this explosive can cause extensive shrapnel damage, and should be treated with extreme caution.

Silver fulminate was first prepared in 1800 by Edward Charles Howard in his research project to prepare a large variety of fulminates. Since its discovery it mainly has been useful solely as a curiosity explosive in toys and tricks.

Structure

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^[1]. The trigonal polymorph consists of cyclic hexamers, (AgCNO)₆.^[2]

Preparation

This compound can be prepared by the reaction of concentrated nitric acid with silver metal and ethyl alcohol, under careful control of the reaction conditions, to avoid explosion.^{[citation needed]} Only very tiny amounts of silver fulminate should be prepared at once, as even the weight of the crystals can cause them to self-detonate.

Silver fulminate can be prepared unintentionally, when an acidic solution of silver nitrate comes in contact with alcohol. This is a hazard in e.g. chemical silvering of mirrors.

Uses

Silver fulminate, often in combination with potassium chlorate, is used in trick noise-makers known as "crackers", "snappers", "pop-its", or "bang-snaps", a popular type of novelty firework.

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. It may be a synonym of silver fulminate. It may also refer to a mixture decomposition product of Tollen's reagent, or an alchemical substance, neither of which may contain the fulminate anion.^{[citation needed]}

References

Further reading

• K. Singh (1959). "Crystal structure of silver fulminate". Acta Cryst. 12: 1053. doi:10.1107/S0365110X5900295X. 

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