Calcium sulfite

Calcium sulfite

Names
IUPAC name Calcium sulfite
Identifiers
CAS Registry Number	10257-55-3 (anhydrous) Y 72878-03-6 (tetrahydrate) 29501-28-8 (hemihydrate)
ChemSpider	8329549 Y
EC number	233-596-8
InChI InChI=1S/Ca.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2 Y N InChI=1/Ca.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2 Key: GBAOBIBJACZTNA-NUQVWONBAU
Jmol-3D images	Image
SMILES [Ca+2].[O-]S([O-])=O
UNII	7078964UQP N
Properties
Chemical formula	CaSO3
Molar mass	120.17g/mol
Appearance	White solid
Melting point	600 °C (1,112 °F; 873 K)
Solubility in water	4.3mg/100mL (18°C)
Hazards
Flash point	Non-flammable
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is: Y/N?)
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 CaSO₃·½(H₂O) and CaSO₃·4(H₂O). All forms are white solids.

Production

It can be produced at laboratory scale by adding Calcium chloride into a solution of Sodium metabisulfite, forming quickly as a precipitate.

Uses

• Synthesizing sodium nitrite and potassium nitrite from their respective nitrates.

Structure

• 

  Structure of the [Ca₃(SO₃)₂(H₂O)₁₂]²⁺ cage in calcium sulfite tetrahydrate.

• 

  Structure of anhydrous CaSO₃.

Natural occurrence

Calcium sulfite(III) hemihydrate occurs in the nature as the rare mineral hannebachite.

See also

• Sodium sulfite
• Sodium bisulfite
• Sodium metabisulfite