Silver bromide, photosensitization

Silver bromide is significantly more photosensitive than silver chloride, resulting in the extensive use of silver bromide in photographic products. 

Photosensitization. Bon (Bll) proposed the following method. Press the wet strip against silver bromide paper, expose for a short period to light, develop with a hard developing bath, and fix immediately with concentrated potassium metabisulfite. Protein at 1 (xg/mm3 gave a distinct spot on the photographic paper. 

Sodium and potassium bromide are mainly utilized in the manufacture of silver bromide for photosensitive layers. Utilization as a sedative has declined. 

Photography. Silver is of the utmost importance in photography, about 30% of the industrial consumption going into this application. Actually, the use of silver in photography is due to the ability of silver-halide crystals (i.e., especially silver bromide) to be photosensitive and undergo a secondary image amplification called development. 

A large quantity of silver is used within photography. The photosensitive layer, which darkens on exposure to light, is mainly silver bromide in a gelatin emulsion. Digital imaging may be a threat to this sector of silver use. 

Fluoride, chloride, bromide, and iodide derivatives of thallium(I) are well known. Their solubilities and photosensitivity are similar to the corresponding silver(I) systems. TIE is water-soluble, whereas the chlorides, bromides, and iodides are water-insoluble solids. This property is exploited in ligand-transfer chemistry involving thallium precursors. Some solid-state structures of thal-lium(I) salts of weakly coordinated anions show TT -halide interactions. Selective abstraction of a fluoride from a C-F bond, leading to thallium fluoride, has been described. The compound [ P(CH2CH2PPh2)3 RuH( 7 -ClTl)]PF6 represents the first metal complex containing an 77 -Cl-bonded TlCl ligand. This compound act as a thallium(I)-ion carrier. 

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