Calcium sulphite

Calcium sulfite

Names
IUPAC name Calcium sulfite
Other names Sulfurous acid, calcium salt (1:1) E226
Identifiers
CAS Number	(anhydrous), 72878-03-6 (tetrahydrate), 29501-28-8 (hemihydrate) 10257-55-3 (anhydrous), 72878-03-6 (tetrahydrate), 29501-28-8 (hemihydrate) Y
3D model (Jmol)	Interactive image
ChemSpider	8329549 Y
ECHA InfoCard	100.030.529
E number	E226 (preservatives)
PubChem CID	159274
UNII	7078964UQP N
InChI InChI=1S/Ca.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2 Y InChI=1/Ca.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2 Key: GBAOBIBJACZTNA-NUQVWONBAU
SMILES [Ca+2].[O-]S([O-])=O
Properties
Chemical formula	CaSO3
Molar mass	120.17 g/mol
Appearance	white solid
Melting point	600 °C (1,112 °F; 873 K)
Solubility in water	0.0043 g/100 mL, 18C
Hazards
Flash point	Non-flammable
Related compounds
Other anions	Calcium sulfate
Other cations	Sodium sulfite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

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 ${\displaystyle {\ce {CaSO3.1/2H2O}}}$ and ${\displaystyle {\ce {CaSO3.4H2O}}}$. All forms are white solids. It is most notable as the product of flue-gas desulfurization.

Calcium sulfite is generated as the intermediate in the production of gypsum, which is the main component of drywall. A typical US home contains 7 metric tons of such drywall gypsum board.