Molecular formula: (NH4)2S2O3 CAS NUMBER: 7783-18-8 Used as fixer for takingPhotographic s,key component of silvering

3. Molecular formula: (NH4)2S2O34. CAS NUMBER: 7783-18-85. Molecular weight:148.206. Properties:. Colorless transparent liquid or white crystal. Relative density of crystal: 1.679,easily soluble in water,insoluble in alcohol, ether,slightly soluble in acetone. 7. Quality standard:

Index name	Liquid	Solid
Assay	56~60%	≥98%
Appearance	colorless transparent Liquid	white crystal
Ammonium sulfite	≤1.0%	≤1.0%
Alkalinity	0.3~1.5%	≤0.4%
Insoluble matter ( precipitation of Ca and Mg)	≤0.2%	---
Heavy metals(as Pb)	≤0.001%	≤0.002%
Fe	≤0.00025%	≤0.001%
Sulfide(as s)	≤0.0002%	≤0.0002%
Ignition residual	≤0.1%	≤0. 2%
Specific gravity	1.310~1.335	----

.Uses: Used as fixer for takingPhotographic s,key component of silvering electrobath, shielding effect agent, casting protectant of Al-Mg alloy, bactericide and analytical reagent.

Ammonium thiosulphate