Calcium oxide
CAS 1305-78-8CaO56.08 g/mol
Calcium oxide is a member of the class of calcium oxides of calcium and oxygen in a 1:1 ratio. It has a role as a fertilizer.
IUPAC: oxocalcium
PubChem
Physical & Chemical Properties
| Melting Point | 4662 °F (NIOSH, 2024) |
| Boiling Point | 5162 °F at 760 mmHg (NIOSH, 2024) |
| Density | 3.3 at 68 °F (USCG, 1999) - Denser than water; will sink |
| Solubility | Reacts with water (NIOSH, 2024) |
| Flash Point | Not flammable |
| Vapor Pressure | 0 mmHg (approx) (NIOSH, 2024) |
| pH | SATURATED SOLN IN WATER IS ABOUT 12.8 |
| Appearance | Calcium oxide appears as an odorless, white or gray-white solid in the form of hard lumps. A strong irritant to skin, eyes and mucous membranes. Used in insecticides and fertilizers. |
Data: PubChem · Last updated: 4/20/2026
GHS Classification
No GHS classification data available.
Classification data is sourced from ECHA.
Regulatory Compliance
TSCA
Listed
note: Status based on EPA TSCA Active Inventory · inventory name: TSCA Chemical Substance Inventory
View sourceGlobal Trade Intelligence
No trade flow data available for this chemical.
HS Code(s): 2522
Data: UN Comtrade
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