Magnesium sulfite is the
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ...
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...
of
sulfurous acid
Sulfurous acid (also sulfuric(IV) acid, sulphurous acid (UK), sulphuric(IV) acid (UK)) is the chemical compound with the formula . There is no evidence that sulfurous acid exists in solution, but the molecule has been detected in the gas phase ...
with the formula . Its most common hydrated form has 6 water molecules making it a
hexahydrate
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was unders ...
, ·6. When heated above , it is dehydrated to magnesium sulfite
trihydrate, or ·3. The anhydrous form is
hygroscopic
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...
, meaning that it readily absorbs water from the air.
See also
*
Calcium sulfite
Calcium sulfite, or calcium sulphite, is a chemical compound, the calcium salt of sulfite with the formula CaSO3·x(H2O). Two crystalline forms are known, the hemihydrate and the tetrahydrate, respectively CaSO3·½(H2O) and CaSO3·4(H2O). All fo ...
*
Magnesium sulfate
Magnesium sulfate or magnesium sulphate (in English-speaking countries other than the US) is a chemical compound, a salt with the formula , consisting of magnesium cations (20.19% by mass) and sulfate anions . It is a white crystalline solid, ...
(Epsom salt)
References
solubility tables of MgSO3 hydrates PDF
H.D.Lutz, Dept. of Chemistry, University of Slegen.{{Magnesium compounds
Magnesium compounds
Sulfites