Silver nitrate
From Wikipedia, the free encyclopedia
| Silver nitrate | ||
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| General | ||
| Molecular formula | AgNO3 | |
| Molar mass | 169.8731 g/mol | |
| Appearance | white solid | |
| CAS number | 7761-88-8 | |
| Properties | ||
| Density and phase | 4.35 g/cm3, solid | |
| Solubility in water | 219 g/100 ml (20 °C) | |
| Melting point | 212 °C | |
| Boiling point | 444 °C decomp. | |
| Structure | ||
| Coordination geometry |
Trigonal Pyramidal | |
| Crystal structure | rhombohedral | |
| Hazards | ||
| MSDS | External MSDS | |
| EU classification | Corrosive (C) Dangerous for the environment (N) |
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| NFPA 704 |
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| R-phrases | R34, R50/53 | |
| S-phrases | S1/2, S26, S45, S60, S61 |
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| Flash point | non-flammable | |
| Supplementary data page | ||
| Structure and properties |
n, εr, etc. | |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
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| Spectral data | UV, IR, NMR, MS | |
| Related compounds | ||
| Other anions | ? | |
| Other cations | Copper(II) nitrate | |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Silver nitrate is a chemical compound with chemical formula AgNO3. This nitrate of silver is the light-sensitive ingredient in photographic film and is a corrosive compound. Soluble silver salts tends to be very toxic to bacteria and other lower life forms. The classic black and white film would be made using silver bromide which is made from silver nitrate. The compound notably stains skin a greyish or black color that is made visible after exposure to sunlight.
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[edit] Synthesis
Silver nitrate crystals can be produced by dissolving silver metal in a solution of nitric acid and evaporating the solution. The equation is as follows: 3Ag(s) + 4HNO3(aq) → 3AgNO3(aq) + 2H2O(l) + NO(g)
[edit] Applications
[edit] Photography
When making photographic film, silver nitrate is reacted with halide salts of sodium or potassium to form insoluble silver halide in situ in photographic gelatin, which is then applied to strips of tri-acetate or polyester. Photons from sunlight, X-rays or other sources, initiate a chemical chain reaction: when photons strike silver halide crystals, they free electrons from the halide ions. These free electrons roam through the crystal and settle in structural imperfections called sensitivity specks. These specks attract positive silver ions, which are then neutralized to form groups of stable silver atoms, creating a latent image that is chemically developed to reveal a photographic image.
[edit] Explosives
Silver nitrate is used to prepare some silver-based explosives, such as the fulminate, azide, or acetylide, through a precipitation reaction.
[edit] Electrochemistry
Silver nitrate may be used to electroplate metals if dissolved in water.
[edit] Medicine
Silver nitrate has antiseptic properties. It is sometimes dropped into newborn babies' eyes at birth to prevent contraction of gonorrhoea or chlamydia from the mother. Eye infections and blindness of newborns is reduced by this method. This method was invented by Credé in 1881 and is still in use.[1][2][3] Disposal of even small quantities of silver nitrate in toilets connected to a septic tank is guaranteed to destroy the septic bacteria and necessitate pumping out and flushing and seeding with fresh bacteria. Fused silver nitrate, shaped into sticks, was traditionally called lunar caustic. It is used as a cauterizing agent. A physician in Canada named Dr. Ringrose used silver nitrate in experimental research by conducting sterilization procedures on women. He was a specialist in obstetrics and gynaecology who believed that the corrosive properties of silver nitrate could be used to block and corrode the fallopian tubes, in a process that he called "office tubal sterilization". See Cryderman v. Ringrose (1978), 89 D.L.R. (3d) 32 (Alta S.C.) and Zimmer et. al v. Ringrose (1981) 4 W.W.R. 75 (Alta C.A.). The malpractice suits were not successful even though the silver nitrate technique didn't work (in fact at least two women ended up having to undergo abortions.)
- Some dentists will use silver nitrate infused swabs to heal mouth ulcers
[edit] Biology
In histology, silver nitrate is used for silver staining, for demonstrating proteins and nucleic acids. For this reason it is also used to demonstrate proteins in PAGE gels. It is also used as a stain in scanning electron microscopy.
[edit] Toxicity
As with all silver salts, silver nitrate is toxic. Ingesting as little as 2 grams can be fatal. Often, milk or egg white can be used to treat individuals who have swallowed silver nitrate, because since they contain denatured protein, the carboxyl and free –SH groups of these products bind to the Ag in its ionic form.
[edit] In fiction
- In The Five People You Meet in Heaven, by Mitch Albom, the Blue Man became blue because he took too much silver nitrate, and the poison turned his skin gray, then blue.
- Lunar Caustic is the name of a novel by Under the Volcano author Malcolm Lowry, published posthumously in 1968.
- A site related to the marketing of the upcoming Nine Inch Nails concept album Year Zero features a sound file with a character known simply as an "Angry Sniper" who decimates people at Wrigley Field with bombs filled with silver nitrite.
- In the film Underworld, bullets containing silver nitrate are used as a weapon against Lycans (werewolves).
