Silver salts
Silver salts are ionic compounds that contain silver as a cation . In most cases the silver ion is simply positively charged and has strong oxidizing properties, since its standard potential is 0.779 V. The detection of silver ions is mostly done by the very sensitive precipitation as chloride .
history
In 1717 Johann Heinrich Schulze demonstrated the sensitivity of silver salts to light.
use
Silver halides , especially silver bromide , are used in the form of small crystals in analog photography as light-sensitive material, since they can be radiolytically split by light , which releases elemental silver, the so-called silver nucleus . The latent image emerges. During development, this silver seed catalyzes the conversion of the remaining silver bromide crystal into elemental silver, which makes the image visible. Without special sensitization of the emulsion, the crystals respond primarily to shades of blue and ultraviolet .
Silver salts, particularly silver nitrate , have found use in medicine because of their antibacterial properties. However, since the introduction of antibiotics , this has largely become obsolete; they are only used as eye drops to prevent a certain eye inflammation in newborns. Since more massive problems with antibiotic resistance have arisen, silver has been used more and more again, but mostly no longer as a salt, but in elemental form as a metal or colloid .
Potassium-silver-cyanide is used for galvanic silvering.
Important silver salts
The silver halides include silver (I) fluoride (AgF), silver chloride (AgCl), silver bromide (AgBr) and silver iodide (AgI).
Other important silver salts are silver nitrate AgNO 3 , silver fulminate (Knallsilber, AgCNO), silver azide AgN 3 and silver sulfide Ag 2 S.
safety instructions
Silver compounds are considered to be highly hazardous to water and are therefore classified in water hazard class 3. If the salts are soluble, they can be precipitated as halides or converted directly into metallic silver by reducing agents , which can then be separated off.
Highly explosive silver nitride (Ag 3 N) can be formed with the nitrate ions from silver-diammine complexes ([Ag (NH 3 ) 2 ] + ) (or Tollens reagent ) , so that such solutions must be reduced.
See also
- Colloidal Silver
- Photographic process (application)