Back Kalsiumsulfaat Afrikaans كبريتات الكالسيوم Arabic Kalsium sulfat Azerbaijani کلسیوم سولفات AZB ক্যালসিয়াম সালফেট Bengali/Bangla Sulfat de calci Catalan Síran vápenatý Czech Calciumsulfat Danish Calciumsulfat German Sulfato de calcio Spanish

Calcium sulfate

Calcium sulfate
Calcium sulfate hemihydrate powder
Calcium sulfate hemihydrate powder
Calcium sulfate hemihydrate
Names
IUPAC name
Calcium sulfate
Other names
Sulfate of lime
Plaster of Paris
Drierite
Gypsum
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 136.141 g/mol (anhydrous)
145.149 g/mol (hemihydrate)
172.171 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)
dihydrate
2.63 g/L (25 °C)[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 an inorganic salt with the chemical formula CaSO
4. It occurs in several hydrated forms; the anhydrous state (known as anhydrite) is a white crystalline solid often found in evaporite deposits. Its dihydrate form is the mineral gypsum, which may be dehydrated to produce bassanite, the hemihydrate state. Gypsum occurs in nature as crystals (selenite) or fibrous masses (satin spar), typically colorless to white, though impurities can impart other hues. All forms of calcium sulfate are sparingly soluble in water[5] and cause permanent hardness when dissolved therein.

  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
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