Calcium carbonate
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| Names | |||
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IUPAC name
Calcium carbonate
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| Other names | |||
| Identifiers | |||
471-34-1 
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| 3D model (Jmol) |
Interactive image Interactive image |
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| ChEBI |
CHEBI:3311
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| ChEMBL |
ChEMBL1200539 
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| ChemSpider |
9708
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| ECHA InfoCard | 100.119.341 | ||
| EC Number | 207-439-9 | ||
| E number | E170 (colours) | ||
| KEGG |
D00932
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| PubChem | 10112 | ||
| RTECS number | FF9335000 | ||
| UNII |
H0G9379FGK
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| Properties | |||
| CaCO3 | |||
| Molar mass | 100.0869 g/mol | ||
| Appearance | Fine white powder; chalky taste | ||
| Odor | odorless | ||
| Density | 2.711 g/cm3 (calcite) 2.83 g/cm3 (aragonite) |
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| Melting point | 1,339 °C (2,442 °F; 1,612 K) (calcite) 825 °C (1517 °F; 1,098 K) (aragonite) |
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| Boiling point | decomposes | ||
| 0.013 g/L (25 °C) | |||
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Solubility product (Ksp)
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3.3×10−9 | ||
| Solubility in dilute acids | soluble | ||
| Acidity (pKa) | 9.0 | ||
| -38.2·10−6 cm3/mol | |||
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Refractive index (nD)
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1.59 | ||
| Structure | |||
| Trigonal | |||
| 32/m | |||
| Thermochemistry | |||
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Std molar
entropy (S |
93 J·mol−1·K−1 | ||
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Std enthalpy of
formation (ΔfH |
−1207 kJ·mol−1 | ||
| Pharmacology | |||
| A02AC01 (WHO) A12AA04 (WHO) | |||
| Hazards | |||
| Safety data sheet | ICSC 1193 | ||
| NFPA 704 | |||
| Flash point | 825 °C (1,517 °F; 1,098 K) | ||
| Lethal dose or concentration (LD, LC): | |||
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LD50 (median dose)
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6450 mg/kg (oral, rat) | ||
| US health exposure limits (NIOSH): | |||
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PEL (Permissible)
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TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp) | ||
| Related compounds | |||
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Other anions
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Calcium bicarbonate | ||
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Other cations
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Magnesium carbonate Strontium carbonate Barium carbonate |
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Related compounds
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Calcium sulfate | ||
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is ?) |
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| Infobox references | |||
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite (most notably as limestone, which contains both of those minerals) and is the main component of pearls and the shells of marine organisms, snails, and eggs. Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale. It is medicinally used as a calcium supplement or as an antacid, but excessive consumption can be hazardous.
Calcium carbonate shares the typical properties of other carbonates. Notably,
Calcium carbonate will react with water that is saturated with carbon dioxide to form the soluble calcium bicarbonate.
This reaction is important in the erosion of carbonate rock, forming caverns, and leads to hard water in many regions.
An unusual form of calcium carbonate is the hexahydrate, ikaite, CaCO3·6H2O. Ikaite is stable only below 6 °C.
The vast majority of calcium carbonate used in industry is extracted by mining or quarrying. Pure calcium carbonate (e.g. for food or pharmaceutical use), can be produced from a pure quarried source (usually marble).
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Wikipedia