Английская Википедия:Ammonium thiosulfate

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Шаблон:Chembox

Ammonium thiosulfate (ammonium thiosulphate in British English) is an inorganic compound with the formula Шаблон:Chem2. It is white crystalline solid with ammonia odor, readily soluble in water, slightly soluble in acetone and insoluble in ethanol and diethyl ether.[1]

Production

It is produced by treating ammonium sulfite with sulfur at temperatures between 85 and 110 °C:[2]

Шаблон:Chem2

Applications

Ammonium thiosulfate is used in photographic fixer. It is a so-called rapid fixer, acting more quickly than sodium thiosulfate fixers.[3] Fixation involves these chemical reactions (illustrated for silver bromide):[4]

Шаблон:Chem2
Шаблон:Chem2

Ammonium thiosulfate is also used for leaching of gold and silver. It works with presence of copper as a catalyst here. This process is a nontoxic alternative gold cyanidation.[5] The advantage to ammonium thiosulfate is that the pyrolysis of its silver complexes leaves a residue solely of silver sulfide, in contrast to complexes derived from sodium thiosulfate.[2]

Other

Ammonium thiosulfate can be used as a fertilizer.[6] As suggested by some research studies, it can also be used as an additive to coal-waste mixtures to reduce formation of dioxins and furans during combustion.[7]

Safety

LD50 (oral, rat) is 2890 mg/kg.[2]

See also

References

Шаблон:Ammonium salts