Calcium sulfite

Structural formula
General
Surname	Calcium sulfite
other names	sulphurous lime Calcium sulfuratum E  226
Molecular formula	CaSO 3
Brief description	white powder (dihydrate)
External identifiers / databases
CAS number 10257-55-3 (anhydrous) 10035-03-7 (dihydrate) EC number 233-596-8 ECHA InfoCard 100.030.529 PubChem 10154041 Wikidata Q899410
properties
Molar mass	120.17 g mol −1
Physical state	firmly
density	3.33 g cm −3
solubility	practically insoluble in water and slightly soluble in ethanol (dihydrate)
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Calcium sulfite is a chemical compound from the group of sulfites . It is a salt of sulphurous acid and is usually in the form of a hydrate (hemihydrate, dihydrate).

Extraction and presentation

Calcium sulfite, like calcium hydrogen sulfite, can be obtained through the action of sulfur dioxide in calcium carbonate or calcium lye dissolved in water ( lime water sample ). The solution is then converted into crystals by drying or evaporation.

${\displaystyle \mathrm {CaCO_{3}+SO_{2}\longrightarrow CaSO_{3}+CO_{2}} }$

${\displaystyle \mathrm {Ca(OH)_{2}+SO_{2}\longrightarrow CaSO_{3}+H_{2}O} }$

properties

Calcium sulfite can be converted by oxidation into calcium sulphate to be converted.

${\displaystyle \mathrm {2\ CaSO_{3}+O_{2}\longrightarrow 2\ CaSO_{4}} }$

It has an orthorhombic crystal structure.

use

Calcium sulfite, in the form of the food additive E 226, serves as a preservative , color stabilizer and antioxidant . In the paper-making calcium is called pulping chemical during sulfite used.

Individual evidence

1. ↑ Entry on E 226: Calcium sulphite in the European database for food additives, accessed on June 27, 2020.
2. ↑ ^{a b c} Physical constants of inorganic compounds (PDF; 391 kB)
3. ↑ ^{a b} Jean Dans, Ellen Lax; Paperback for chemists and physicists Vols. 1–3: Elements, inorganic compounds and materials, minerals: Vol. III; ISBN 978-3540600350
4. ↑ ^{a b} Entry on calcium sulphite in the GESTIS substance database of the IFA , accessed on February 28, 2017(JavaScript required) .
5. ↑ Patent-de: Process for the oxidation of calcium sulfite to calcium sulfate in aqueous suspensions
6. ↑ by Wolf-Eckhard Gudemann: I'll tell you everything - Wolf-Eckhard Gudemann . Wissenmedia Verlag, 2007, ISBN 3-577-10292-6 , pp. 304 ( limited preview in Google Book Search).
7. ↑ by Werner Baumann, Bettina Herberg-Liedtke: Paper chemicals: data and facts on environmental protection - Werner Baumann, Bettina Herberg-Liedtke . Springer DE, 1994, ISBN 3-540-57593-6 , pp. 503 ( limited preview in Google Book search).