Methanedisulfonic acid

Methanedisulfonic acid
Names
	Preferred IUPAC name Methanedisulfonic acid
	Other names methionic acid
Identifiers
CAS Number	503-40-2;
3D model (JSmol)	Interactive image;
ChemSpider	9998;
ECHA InfoCard	100.007.243
EC Number	207-966-4;
PubChem CID	10427;
UNII	55N1VUX48W;
CompTox Dashboard (EPA)	DTXSID3060118 ;
	InChI InChI=1S/CH4O6S2/c2-8(3,4)1-9(5,6)7/h1H2,(H,2,3,4)(H,5,6,7) Key: OPUAWDUYWRUIIL-UHFFFAOYSA-N;
	SMILES C(S(=O)(=O)O)S(=O)(=O)O;
Properties
Chemical formula	CH4O6S2
Molar mass	176.16 g·mol−1
Appearance	colourless solid
Melting point	138–140 °C (280–284 °F; 411–413 K) decomposes: 209-210 °C
Solubility in water	miscible
Acidity (pKa)	-0.71 (predicted)
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H413
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Methanedisulfonic acid is the organosulfur compound with the formula CH₂(SO₃H)₂. It is the disulfonic acid of methane. It is prepared by treatment of methanesulfonic acid with oleum. Its acid strength (pK_a) is comparable to that of sulfuric acid.^[3]

References

^ Goldwhite, H.; Gibson, M.S.; Harris, C. (January 1965). "Free radical addition reactions—IV". Tetrahedron. 21 (10): 2743–2747. doi:10.1016/S0040-4020(01)98360-7.
^ Swan, G. A.; Satchell, D. P. N.; Sykes, K. W.; Michelson, A. M.; Boyd, A. N.; Southern, P. F.; Waters, William A.; Cummings, W. A. W.; Harvey, W. E.; Moore, C. G.; Porter, M.; Menzies, I. A.; Owen, L. W.; Mulley, B. A.; de Ruyter van Steveninck, A. W.; Taylor, E. P. (1958). "Notes". Journal of the Chemical Society (Resumed): 2051–2068. doi:10.1039/JR9580002051. See note at pages 2058-2060; Cummings, W. A. W. "Some New Sulphur-containing Diacids".
^ Kosswig, Kurt (2000). "Sulfonic Acids, Aliphatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a25_503. ISBN 3527306730.