Sodium thiosulfate

Sodium thiosulfate
Names
	IUPAC name Sodium thiosulfate
	Other names Sodium hyposulphite; Hyposulphite of soda; Hypo
Identifiers
CAS Number	anhydrous: 7772-98-7 ; pentahydrate: 10102-17-7 ;
3D model (JSmol)	anhydrous: Interactive image; pentahydrate: Interactive image;
ChEBI	anhydrous: CHEBI:132112 ;
ChEMBL	pentahydrate: ChEMBL2096650 ;
ChemSpider	anhydrous: 22885 ;
ECHA InfoCard	100.028.970
EC Number	anhydrous: 231-867-5;
E number	E539 (acidity regulators, ...)
PubChem CID	anhydrous: 24477;
RTECS number	anhydrous: XN6476000;
UNII	anhydrous: L0IYT1O31N ; pentahydrate: HX1032V43M ;
CompTox Dashboard (EPA)	anhydrous: DTXSID9042417 ;
	InChI InChI=1S/2Na.H2O3S2/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2+1;/p-2 Key: AKHNMLFCWUSKQB-UHFFFAOYSA-L ; anhydrous: InChI=1/2Na.H2O3S2/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2+1;/p-2 Key: AKHNMLFCWUSKQB-NUQVWONBAM; pentahydrate: InChI=1S/2Na.H2O3S2.5H2O/c;;1-5(2,3)4;;;;;/h;;(H2,1,2,3,4);51H2/q2+1;;;;;;/p-2 Key: PODWXQQNRWNDGD-UHFFFAOYSA-L;
	SMILES anhydrous: [Na+].[Na+].[O-]S(=O)(=O)[S-]; pentahydrate: O.O.O.O.O.[Na+].[Na+].[O-]S(=O)(=O)[S-];
Properties
Chemical formula	Na2S2O3
Molar mass	158.11 g/mol (anhydrous) ; 248.18 g/mol (pentahydrate)
Appearance	White crystals
Odor	Odorless
Density	1.667 g/cm3
Melting point	48.3 °C (118.9 °F; 321.4 K) (pentahydrate)
Boiling point	100 °C (212 °F; 373 K) (pentahydrate, - 5H2O decomposition)
Solubility in water	70.1 g/100 mL (20 °C) ; 231 g/100 mL (100 °C)
Solubility	negligible in alcohol
Refractive index (nD)	1.489
Structure
Crystal structure	monoclinic
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
NFPA 704 (fire diamond)	1 0 0
Flash point	Non-flammable
Safety data sheet (SDS)	External MSDS
Related compounds
Other cations	Thiosulfuric acid; Lithium thiosulfate; Potassium thiosulfate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Sodium thiosulfate (sodium thiosulphate) is an inorganic compound with the formula Na₂S₂O₃·(H₂O)_x. Typically it is available as the white or colorless pentahydrate (x = 5), which is a white solid that dissolves well in water. The compound is a reducing agent and a ligand, and these properties underpin its applications.

Names


IUPAC name Sodium thiosulfate
Other names Sodium hyposulphite Hyposulphite of soda Hypo
Identifiers
CAS Number	anhydrous: 7772-98-7^Y pentahydrate: 10102-17-7^Y
3D model (JSmol)	anhydrous: Interactive image pentahydrate: Interactive image
ChEBI	anhydrous: CHEBI:132112^N
ChEMBL	pentahydrate: ChEMBL2096650^Y
ChemSpider	anhydrous: 22885^Y
ECHA InfoCard	100.028.970
EC Number	anhydrous: 231-867-5
E number	E539 (acidity regulators, ...)
PubChem CID	anhydrous: 24477
RTECS number	anhydrous: XN6476000
UNII	anhydrous: L0IYT1O31N^Y pentahydrate: HX1032V43M^Y
CompTox Dashboard (EPA)	anhydrous: DTXSID9042417
InChI InChI=1S/2Na.H2O3S2/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2+1;/p-2^Y Key: AKHNMLFCWUSKQB-UHFFFAOYSA-L^Y anhydrous: InChI=1/2Na.H2O3S2/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2+1;/p-2 Key: AKHNMLFCWUSKQB-NUQVWONBAM pentahydrate: InChI=1S/2Na.H2O3S2.5H2O/c;;1-5(2,3)4;;;;;/h;;(H2,1,2,3,4);51H2/q2+1;;;;;;/p-2 Key: PODWXQQNRWNDGD-UHFFFAOYSA-L
SMILES anhydrous: [Na+].[Na+].[O-]S(=O)(=O)[S-] pentahydrate: O.O.O.O.O.[Na+].[Na+].[O-]S(=O)(=O)[S-]
Properties
Chemical formula	Na₂S₂O₃
Molar mass	158.11 g/mol (anhydrous) 248.18 g/mol (pentahydrate)
Appearance	White crystals
Odor	Odorless
Density	1.667 g/cm³
Melting point	48.3 °C (118.9 °F; 321.4 K) (pentahydrate)
Boiling point	100 °C (212 °F; 373 K) (pentahydrate, - 5H₂O decomposition)
Solubility in water	70.1 g/100 mL (20 °C) 231 g/100 mL (100 °C)
Solubility	negligible in alcohol
Refractive index (n_D)	1.489
Structure
Crystal structure	monoclinic
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
NFPA 704 (fire diamond)	1 0 0
Flash point	Non-flammable
Safety data sheet (SDS)	External MSDS
Related compounds
Other cations	Thiosulfuric acid Lithium thiosulfate Potassium thiosulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references