Thiosulfates

Abstract

The thiosulfate ion has two inequivalent sulfur atoms, leading to interesting chemical properties. Thiosulfates are used primarily in photography as a fixative to dissolve undeveloped silver halide from negatives or prints. Either the sodium salt, also known as hypo, or the ammonium salt, ammo hypo, is employed in the photographic industry. The latter is also used for dechlorination of potable water and in flue gas‐desulfurization. A gold thiosulfate has been used in treatments for rheumatoid arthritis.