Calcium sulfate

Calcium sulfate
Calcium sulfate hemihydrate
Names
Other names
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.029.000 Edit this at Wikidata
EC Number
  • 231-900-3
E number E516 (acidity regulators, ...)
7487
KEGG
RTECS number
  • WS6920000
  • (dihydrate): MG2360000
UNII
  • InChI=1S/Ca.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 checkY
    Key: OSGAYBCDTDRGGQ-UHFFFAOYSA-L checkY
  • InChI=1/Ca.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2
    Key: OSGAYBCDTDRGGQ-NUQVWONBAU
  • [Ca+2].[O-]S([O-])(=O)=O
Properties
CaSO4
Molar mass 136.14 g/mol (anhydrous)
145.15 g/mol (hemihydrate)
172.172 g/mol (dihydrate)
Appearance white solid
Odor odorless
Density 2.96 g/cm3 (anhydrous)
2.32 g/cm3 (dihydrate)
Melting point 1,460 °C (2,660 °F; 1,730 K) (anhydrous)
0.26 g/100ml at 25 °C (dihydrate)[1]
4.93 × 10−5 mol2L−2 (anhydrous)
3.14 × 10−5 (dihydrate)
[2]
Solubility in glycerol slightly soluble (dihydrate)
Acidity (pKa) 10.4 (anhydrous)
7.3 (dihydrate)
-49.7·10−6 cm3/mol
Structure
orthorhombic
Thermochemistry
107 J·mol−1·K−1 [3]
-1433 kJ/mol[3]
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Flash point Non-flammable
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp) [for anhydrous form only][4]
REL (Recommended)
TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp) [anhydrous only][4]
IDLH (Immediate danger)
N.D.[4]
Safety data sheet (SDS) ICSC 1589
Related compounds
Other cations
Magnesium sulfate
Strontium sulfate
Barium sulfate
Related desiccants
Calcium chloride
Magnesium sulfate
Related compounds
Plaster of Paris
Gypsum
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. It has many uses in industry. All forms are white solids that are poorly soluble in water.[5] Calcium sulfate causes permanent hardness in water.

  1. ^ Lebedev, A. L.; Kosorukov, V. L. (2017). "Gypsum Solubility in Water at 25°C" (PDF). Geochemistry International. 55 (2): 171–177. Bibcode:2017GeocI..55..205L. doi:10.1134/S0016702917010062. S2CID 132916752.
  2. ^ D.R. Linde (ed.) "CRC Handbook of Chemistry and Physics", 83rd Edition, CRC Press, 2002
  3. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A21. ISBN 978-0-618-94690-7.
  4. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0095". National Institute for Occupational Safety and Health (NIOSH).
  5. ^ Franz Wirsching "Calcium Sulfate" in Ullmann's Encyclopedia of Industrial Chemistry, 2012 Wiley-VCH, Weinheim. doi:10.1002/14356007.a04_555