Calcium oxide
chemical compound
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.
| Names | ||
|---|---|---|
| IUPAC name
Calcium oxide
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| Other names
Quicklime, burnt lime, unslaked lime, pebble lime, calcia
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| Identifiers | ||
3D model (JSmol)
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| ChEBI | ||
| ChEMBL | ||
| ChemSpider | ||
| ECHA InfoCard | 100.013.763 | |
| E number | E529 (acidity regulators, ...) | |
| Gmelin Reference | 485425 | |
PubChem CID
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| RTECS number |
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| UNII | ||
| UN number | 1910 | |
CompTox Dashboard (EPA)
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| 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 ΔfH |
−635 kJ·mol−1[3] | |
| Standard molar entropy S |
40 J·mol−1·K−1[3] | |
| Pharmacology | ||
| QP53AX18 (WHO) | ||
| Hazards | ||
| NFPA 704 |
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| Flash point | Non-flammable | |
| U.S. Permissible exposure limit (PEL) |
TWA 5 mg/m3[4] | |
| Related compounds | ||
| Other anions | Calcium sulfide Calcium hydroxide | |
| Other cations | Beryllium oxide Magnesium oxide Strontium oxide Barium oxide | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | ||
| Infobox references | ||
It is also a base. It reacts with acids to make calcium salts. Quicklime is an important ingredient of cement.
Related pages change
References change
- ↑ 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.
- ↑ Calciumoxid Archived 2013-12-30 at the Wayback Machine. GESTIS database
- ↑ 3.0 3.1 Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A21. ISBN 978-0-618-94690-7.
- ↑ NIOSH Pocket Guide to Chemical Hazards. "#0093". National Institute for Occupational Safety and Health (NIOSH).
