Thiosulfuric acid

Thiosulfuric acid
Names
	IUPAC name Sulfurothioic S-acid
	Systematic IUPAC name Dihydroxidooxidosulfidosulfur
	Other names Thiosulfuric acid; Sulfurothioic O,O-acid
Identifiers
CAS Number	13686-28-7 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:29279 ;
ChemSpider	22886 ;
PubChem CID	24478;
UNII	7K79Y2EKKP ;
CompTox Dashboard (EPA)	DTXSID00159981 ;
	InChI InChI=1S/H2O3S2/c1-5(2,3)4/h(H2,1,2,3,4) Key: DHCDFWKWKRSZHF-UHFFFAOYSA-N ; InChI=1/H2O3S2/c1-5(2,3)4/h(H2,1,2,3,4);
	SMILES OS(=O)(=O)S;
Properties
Chemical formula	H2S2O3
Molar mass	114.13 g·mol−1
Melting point	decomposes below 0 °C
Solubility in water	decomposes
Acidity (pKa)	pKa1 = 0.6; pKa2 = 1.74;
Conjugate base	Thiosulfate
Related compounds
Other cations	Lithium thiosulfate; Sodium thiosulfate; Potassium thiosulfate; Ammonium 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

Thiosulfuric acid is the inorganic compound with the formula H₂S₂O₃. It has attracted academic interest as a simple, easily accessed compound that is labile. It has few practical uses.