Silver fulminate (AgCNO) is a highly explosive silver salt of fulminic acid . Silver fulminate is a primary explosive , but has limited use due to its extreme sensitivity to impact, heat, pressure, and electricity. The compound gradually becomes sensitive as it accumulates even in small amounts; The touch of a falling feather , the impact of a droplet of water or a small static discharge , are all capable of explosively detonating a crude pile of silver no larger than a dime and no heavier than a few milligrams . It is impossible to collect in large quantities due to the compound’s tendency to self-explode 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 large enough for commercial use. Detonators using silver fulminate were used to introduce picric acid in 1885 , but have since been used only by the Italian Navy . [3] Current commercial use is in the production of non-harmful novelty noisemakers as children’s toys and tricks.
structure
Silver fulminate occurs in two polymorphic forms , an orthorhombic one and a triangular one with a rhombohedral lattice . [4] The trivalent polymorph consists of cyclic hexamers, (AGCNO) 6 .
Property
Fulminates are very toxic, almost similar to cyanide. [3] When pure, silver fulminate is chemically very stable, not decomposing after years of storage. Like many silver salts, it darkens when exposed to light. It is only slightly soluble in cold water and can be re-crystallized using hot water. [3] [6] It can also be recrystallized with a 20% solution of ammonium acetate. [3] It is not hygroscopic and may burst under moisture or water; It was reported to remain explosive even after 37 years under water. [3] It explodes when exposed to concentrated sulfuric acid or chlorine or bromine, but not when exposed to iodine. [3]It is insoluble in nitric acid, but dissolves in ammonia, alkali chloride, alkali cyanides, aniline, pyridine, and potassium iodide 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 adding a solution of silver nitrate to nitric acid in ethanol, under careful control of the reaction conditions, to avoid an explosion. [7] The reaction is usually carried out at 80–90 °C; At 30 °C, the precipitate cannot form. [3] Only a very small amount of silver fulminate should be prepared at a time, as even the weight of the crystals can cause them to self-explode. Another way to make silver fulminate is by reacting silver carbonate with ammonia in solution.
4 Ag 2 CO 3 + 4 NH 3 → 4 AgCNO + 6 H 2 O + 4 Ag + O 2
When nitrogen oxide gas is passed through a solution of silver nitrate in ethanol, silver fulminate is also formed. [3]
Silver fulminate can be prepared inadvertently when an acidic solution of silver nitrate is exposed to alcohol. [7] This is a hazard in some formulations of chemically silvered mirrors.
novelty explosive
Silver fulminate, often in combination with potassium chlorate, in trick noise-makers known as “throw-downs”, “crackers”, “snappers”, “whipersnappers”, “pop-its”, or “bang snaps”. is used to. Popular type of novelty fireworks. They contain about 200 mg of fine gravel, which is coated with a minute amount (about 80 µg) [8] of silver fulminate. When thrown against a hard surface, to produce a short salute by a supersonic explosion, The impact is sufficient to detonate a small amount of explosive. The snaps are designed to be incapable of causing damage (even when blasted against the skin) due to the buffing effect provided by the very high mass of the gravel medium. It is also a chemical found in Christmas crackers [9]Which was first used by Tom Smith in 1860. The chemical is painted on one of the card’s two narrow strips, with the abrasive on the other. When the cracker is pulled, the abrasive explodes into the silver fulminate.
A fulminate mixture containing 10-20% potassium chlorate is cheaper and more lustrous than fulminate alone. [3]
Silver Fulminate and “Fulmating Silver”
Silver fulminate is often confused with silver nitride, silver azide or fulminate silver. “Fulmating silver”, although always referring to an explosive silver-containing substance, is a vague term. While it may be synonymous with silver fulminate, it may also refer to a nitride or azide, the decomposition product of Tollen’s reagent, or a chemical mixture that does not contain the fulminate ion.
Silver Basic Facts
Atomic Number: 47
Symbol: Ag
Atomic Weight : 107.8682
Discovery: Known since prehistoric times. Man learned to separate silver from lead as early as 3000 BC
Electron Configuration : [cri-s.] 5s 1 4 d 10
Word Origin: Anglo-Saxon Sulfur or Sulfur ; Meaning ‘silver’, and Latin argentum meaning ‘silver’
Properties:
Silver has a melting point of 961.93 °C, a boiling point of 2212 °C, a specific gravity of 10.50 (20 °C), with a precipitate of 1 or 2. Pure silver has a white metallic luster. Silver is slightly harder than gold. It is very ductile and malleable, having these properties exceeded by gold and palladium. Pure silver has the highest electrical and thermal conductivity of all metals . Silver has the lowest contact resistance of all metals. Silver is stable in pure air and water, although it tarnishes when exposed to ozone, hydrogen sulfide, or air containing sulfur.
Uses:
Silver alloys have many commercial uses. Sterling silver (92.5% silver, with copper or other metals) is used for silverware and jewelry. Silver is used in photography, dental compounds, solder, brazing, electrical contact, batteries, mirrors and printed circuits. Freshly deposited silver is the best known reflector of visible light, but it rapidly fades and loses its reflection. Silver fulminate (Ag 2 C 2 N 2 O 2 ) is a powerful explosive. Silver iodide is used in cloud seeding to produce rain.Silver chloride can be made transparent and is also used as a cement for glass. Silver nitrate or lunar caustic is used extensively in photography. Although silver is not considered poisonous, most of its salts are toxic, as they also contain ions . Exposure to silver (metals and soluble compounds ) should not exceed 0.01 mg/m3 ( time-weighted average of 8 hours for a 40-hour week ) . Silver compounds can be absorbed into the circulatory system, with less silver deposits in body tissues.This can result in argyria, which is characterized by a greyish pigmentation of the skin and mucous membranes. Silver is disinfectant and can be used to kill many lower organisms without harming higher organisms. Silver is used as a coin in many countries.
Source: Silver is native and ores contain arunitis (Ag 2S ) and horn silver (AgCl). Lead, lead-zinc, copper, copper-nickel and gold ores are other major sources of silver. Commercial fine silver is at least 99.9% pure. Commercial purities of 99.999 +% are available.
Element Classification: Transition Metals
Silver Physical Data
Density (g/cc): 10.5
Appearance: Silver, ductile, malleable metal
Isotopes: Silver has 38 known isotopes ranging from Ag-93 to Ag-130. Silver has two stable isotopes: Ag-107 (51.84% abundance) and Ag-109 (48.16% abundance).
Atomic Radius (Noon): 144
Atomic Volume (cc/mol): 10.3
Covalent Radius (noon): 134
Ionic radius : 89 (+ 2e) 126 (+ 1e)
Specific heat (@ 20 °CJ/g mol): 0.237
Fusion Heat (kJ/mol): 11.95
Heat of vaporization (kJ/mol): 254.1
Debye Temperature (K): 215.00
Pauling Negativity Number: 1.93
First Ionizing Energy (kJ/mol): 730.5
Thermal conductivity: 429 W/m K @ 300 K
Oxidation states : +1 (most common), +2 (less common), +3 (less common)
Reticular Structure: Face Centered Cube
Lattice Constant (Å): 4.090
CAS Registry Number : 7440-22-4
Silver Trivia:
- The element symbol for silver is Ag, from the Latin word argentum which means silver.
- In many cultures, and in some alchemical texts , silver was associated with the moon while gold was associated with the sun.
- Silver has the highest electrical conductivity of all metals.
- Silver has the highest thermal conductivity of all metals.
- Silver halide crystals turn black when exposed to light. This process was crucial to photography.
- Silver is considered one of the best metals .
- Silver is slightly harder (less malleable) than gold.
- Silver ions and silver compounds are toxic to many types of bacteria, algae and fungi. Silver coins were kept in containers of water and wine to prevent spoilage.
- Silver nitrate has been used to prevent infection in burns and other wounds.
