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Calcium oxide

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Calcium oxide
Calcium oxide
Names
IUPAC name
Calcium oxide
Other names
Quicklime, burnt lime, unslaked lime, pebble lime, calcia
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.013.763
E number E529 (acidity regulators, ...)
Gmelin Reference 485425
RTECS number
  • EW3100000
UNII
UN number 1910
  • [Ca]=O
Properties
CaO
Molar mass 56.0774 g/mol
Appearance White to pale yellow/brown powder
Odor Odorless
Density 3.34 g/cm3[1]
Melting point 2,613 °C (4,735 °F; 2,886 K)[1]
Boiling point 2,850 °C (5,160 °F; 3,120 K) (100 hPa)[2]
Reacts to form calcium hydroxide
Solubility in Methanol Insoluble (also in diethyl ether, octanol)
Acidity (pKa) 12.8
−15.0×10−6 cm3/mol
Structure
Cubic, cF8
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−635 kJ·mol−1[3]
Standard molar
entropy
So298
40 J·mol−1·K−1[3]
Pharmacology
QP53AX18 (WHO)
Hazards
NFPA 704

0
3
2
 
Flash point Non-flammable
U.S. Permissible
exposure limit (PEL)
TWA 5 mg/m3[4]
Related compounds
Other anions {{{value}}}
Other cations {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references


Calcium oxide is a chemical compound of calcium and oxygen. Its chemical formula is CaO. It is known as quicklime. It is made in a lime kiln. It releases heat when dissolved in water and changes into calcium hydroxide. It is a white powder.

It is also a base. It reacts with acids to make calcium salts. Quicklime is an important ingredient of cement.

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References

[change | change source]
  1. 1.0 1.1 Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.55. ISBN 1439855110.
  2. Calciumoxid Archived 2013-12-30 at the Wayback Machine. GESTIS database
  3. 3.0 3.1 Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A21. ISBN 978-0-618-94690-7.
  4. NIOSH Pocket Guide to Chemical Hazards. "#0093". National Institute for Occupational Safety and Health (NIOSH).