Magnesium sulfite

Names
IUPAC name Magnesium sulfite
Other names Magnesium sulphite
Identifiers
CAS Number	7757-88-2 Y trihydrate: 19086-20-5 hexahydrate: 13446-29-2
3D model (JSmol)	Interactive image trihydrate: Interactive image hexahydrate: Interactive image
ChemSpider	2282946
ECHA InfoCard	100.028.932
EC Number	231-825-6
PubChem CID	3014583 trihydrate: 22005976 hexahydrate: 22005975
UNII	792J6K230W Y trihydrate: 5AY4M0SU9Y hexahydrate: 517M335CTF
CompTox Dashboard (EPA)	DTXSID50884418 trihydrate: DTXSID60172595 hexahydrate: DTXSID70158724
InChI InChI=1S/Mg.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2 Key: JESHZQPNPCJVNG-UHFFFAOYSA-L trihydrate: InChI=1S/Mg.H2O3S.3H2O/c;1-4(2)3;;;/h;(H2,1,2,3);3*1H2/q+2;;;;/p-2 Key: AGRLKNFKXGZQRX-UHFFFAOYSA-L hexahydrate: InChI=1S/Mg.H2O3S.6H2O/c;1-4(2)3;;;;;;/h;(H2,1,2,3);6*1H2/q+2;;;;;;;/p-2 Key: KLIKMSKEFPRHEE-UHFFFAOYSA-L
SMILES [O-]S(=O)[O-].[Mg+2] trihydrate: O.O.O.[O-]S(=O)[O-].[Mg+2] hexahydrate: O.O.O.O.O.O.[O-]S(=O)[O-].[Mg+2]
Properties
Chemical formula	MgSO 3 (anhydrous); MgSO 3·6H 2O
Molar mass	104.368200 g/mol (anhydrous) 212.4599 g/mol (hexahydrate)
Solubility in water	5.2g/L at 298.2K (hexahydrate)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Magnesium sulfite is the magnesium salt of sulfurous acid with the formula MgSO
₃. Its most common hydrated form has 6 water molecules making it a hexahydrate, MgSO
₃·6H
₂O. When heated above 40 °C (104 °F), it is dehydrated to magnesium sulfite trihydrate, or MgSO
₃·3H
₂O.^[1] The anhydrous form is hygroscopic, meaning that it readily absorbs water from the air.

• Calcium sulfite
• Magnesium sulfate (Epsom salt)

Solubility tables of MgSO₃