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 1. Chemcial name:Sodium thiosulfate2. Structural formula:
 
  3. Molecular formula: Na2S2O3·5H2O
 4. Molecular weight: 248.17
 5. Physical and chemical properties: monoclinic crystal, melting point: 40-45℃, relative density: 1.729(17℃).
 6. Quality index:
 
	
		
			| Item | Photographic grade | Technical grade | Anhydrous grade |  
			| Appearance | colorless transparent crystal | colorless transparent crystal | white powder |  
			| Content | ≥99.00% | ≥98.5% | ≥97.0% |  
			| Water insoluble matter | ≤0.01% | ≤0.03% | ≤0.03% |  
			| Sulfide | ≤0.001% | ≤0.003% | ≤0.001% |  
			| Iron | ≤0.001% | ≤0.003% | ≤0.005% |  
			| PH value | 6.5~9.5 | 6.5~9.5 | 6.5~9.5 |  
			| Aqueous reaction | pass test | pass test | ---- |  
			| Particle size | 12~16 | --- | ---- |  7. Packing: 25kg, 50kg plastic woven bag, or at customer's request.
 8. Uses: in fixing agent, electroplating, leather, reducing agent, dechlorinating agent, fading agent, and other industries.
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