Chemical Properties
Silver chloride(7783-90-6
), AgCl, is a white,granular powder that darkens on exposure to light,finally turning black.It exists in several modifications differing in behavior toward light and solubility in various solvents. Soluble in ammonium hydroxide, concentrated sulfuric acid, and sodium thiosulfate and potassium bromide solutions, very slightly soluble in water, can be melted, cast, and fabricated like a metal. Derived by heating a silver nitrate solution and adding hydrochloric acid or salt solution. The whole is boiled, then filtered. This must take place in the dark or under a ruby-red light. Used in photography,photometry and optics, batteries, photochromic glass,silver plating,production of pure silver, and as an antiseptic. Single crystals are used for infrared absorption cells and lens elements and as a lab reagent
Application
?AgCl is very important as a linear polarizer in the infrared region (λ: 2–23 mm). The refractive index is almost constant in the infrared region and the polarization angle is almost independent of wavelength. The polarization angles are 63°43' (3 mm), 63°20' (10 mm), and 63°33' (20 mm), showing the difference of angle below 18 for λ: 2–23 mm. The polariscope is fabricated typically by arranging the six sheets of plates with the thickness of 0.5 mm in the shape of roof type. Bakelite or plastic is good for the material of the holder case.
Health effects
Silver itself is not toxic to humans, but most silver salts are. In large doses, silver and compounds containing it can be absorbed into the circulatory system and become deposited in various body tissues, leading to argyria, which results in a blue-grayish pigmentation of the skin, eyes, and mucous membranes. Argyria is rare, and although, so far as known, this condition does not otherwise harm a person's health, it is disfiguring and usually permanent. Mild forms of argyria are sometimes mistaken for cyanosis.
Flammability and Explosibility
Nonflammable
Toxicology
Metallic silver is oxidized and may deposit in the tissues, causing arygria. The silver ion is known to inhibit glutathione peroxidase and NA+,K+-ATPase activity, disrupting selenium-catalyzed sulfhydryl oxidation-reduction reactions and intracellular ion concentrations, respectively. Silver nanoparticles are believed to disrupt the mitochondrial respiratory chain, causing oxidative stress, reduced ATP synthesis, and DNA damage.
Purification Methods
Recrystallise it from conc NH3 solution by acidifying with HCl, filtering off the solid, washing it with H2O and drying it in a vacuum. It is soluble in NH3 and should be kept in the dark.
