calcium oxide

Also known as caustic lime, quicklime, calx, calcium monoxide, limestone, burned lime, burnt lime, lime

chemical compound

AI overview

Calcium oxide is a chemical compound made from calcium and oxygen that is commonly produced by heating limestone at high temperatures. It has many practical uses in construction, water treatment, and industrial processes, making it an important material in modern manufacturing and infrastructure.

AI-generated from the Wikipedia summary — may contain errors.

Chemical data

Formula: CaO
Molecular weight: 56.08 g/mol
IUPAC name: oxocalcium
SMILES: O=[Ca]
InChIKey: ODINCKMPIJJUCX-UHFFFAOYSA-N
Polar surface area: 17.1 Å²
H-bond donors: 0
H-bond acceptors: 1
Formal charge: 0

via PubChem

Research

10,410 papers

Effects of Calcium-Oxide-Modified Biochar on the Anaerobic Digestion of Vacuum Blackwater.ReviewMolecules (Basel, Switzerland) · 2025Chiang PF, Zhang TL, Giwa AS et al.DOI: 10.3390/molecules30020215
Advances in the fabrication, modification, and performance of biochar, red mud, calcium oxide, and bentonite catalysts in waste-to-fuel conversion.ReviewEnvironmental research · 2023Nganda A, Srivastava P, Lamba BY et al.DOI: 10.1016/j.envres.2023.116284
Systematic review of antibacterial potential in calcium oxide and silicon oxide nanoparticles for clinical and environmental infection control.Journal of applied biomedicine · 2025Algadi H, Abdelfatah Alhoot M, Yaaqoob LADOI: 10.32725/jab.2025.001
Calcium oxide enhances the anaerobic co-digestion of excess sludge and plant waste: performance and mechanism.Water science and technology : a journal of the International Association on Water Pollution Research · 2024Wang Y, Wang K, Zhou X et al.DOI: 10.2166/wst.2024.268
Calcium oxide adsorption of gas phase PCDD/Fs and its impact on the adsorption properties of activated carbon.Environmental pollution (Barking, Essex : 1987) · 2024Lai J, Wang P, Qi H et al.DOI: 10.1016/j.envpol.2024.124750
Recent Progress in the Development of Disinfectants from Scallop Shell-Derived Calcium Oxide for Clinical and Daily Use.ReviewBiocontrol science · 2021Hata Y, Ishihara M, Hiruma S et al.DOI: 10.4265/bio.26.129
Calcium oxide nanoparticles ameliorate cadmium toxicity in alfalfa seedlings by depriving its bioaccumulation, enhancing photosystem II functionality and antioxidant gene expression.The Science of the total environment · 2024Hussan MU, Hussain S, Adeel M et al.DOI: 10.1016/j.scitotenv.2024.176797
Calcium oxide nanoparticles mitigate lead stress in Abelmoschus esculentus though improving the key antioxidative enzymes, nutritional content and modulation of stress markers.Plant physiology and biochemistry : PPB · 2024Raza HZ, Shah AA, Noreen Z et al.DOI: 10.1016/j.plaphy.2023.108171

via PubMed

Wikidata facts

Mass: 55.958

Show 12 more facts

Commons category: Calcium oxide
density: 3.34
chemical formula: CaO
NIOSH Pocket Guide ID: 0093
immediately dangerous to life or health: 25
melting point: 2927
boiling point: 2850
vapor pressure: 0
time-weighted average exposure limit: 5
canonical SMILES: O=[Ca]
standard enthalpy of formation: -635.09
ionization energy: 6.90

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Article

Calcium oxide (formula: CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term lime connotes calcium-containing inorganic compounds, in which carbonates, oxides, and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate. By contrast, quicklime specifically applies to the single compound calcium oxide. Calcium oxide that survives processing without reacting in building products, such as cement, is called free lime.

Quicklime is relatively inexpensive. Both it and the chemical derivative calcium hydroxide (of which quicklime is the base anhydride) are important commodity chemicals.