Calcium Carbonate

Title: Calcium Carbonate
CAS Registry Number: 471-34-1
CAS Name: Carbonic acid calcium salt (1:1)
Trademarks: Cacit (Norwich); Calcichew (Shire); Calcidia (Roche); Caltrate (Wyeth); Citrical (Shire); Fixical (Pharmascience); Maalox Quick Dissolve (Novartis); Maalox Regular Strength (Novartis); Os-Cal (GSK); Tums Smooth Dissolve (GSK)
Molecular Formula: CCaO3
Molecular Weight: 100.09
Percent Composition: C 12.00%, Ca 40.04%, O 47.96%
Line Formula: CaCO3
Literature References: Exists in nature as the minerals aragonite, calcite and vaterite. Solubility and scale formation study: J.-Y. Gal et al., Talanta 43, 1497 (1996). Clinical evaluation in protease inhibitor-induced diarrhea in HIV: M. J. Turner et al., HIV Clin. Trials 5, 19 (2004). Review of commercial applications in paints, coatings and adhesives: R. D. Athey, Eur. Coatings J. 5, 256-263 (1994).
Properties: Odorless, tasteless powder or crystals. Two crystal forms are of commercial importance: Aragonite, orthorhombic, mp 825° (dec), d 2.83, formed at temps above 30°; Calcite, hexagonal-rhombohedral, mp 1339° (102.5 atm), d25.2 2.711, formed at temps below 30°. At about 825° is dec into CaO and CO2. Practically insol in water. Sol in dil acids.
Melting point: mp 825° (dec); mp 1339° (102.5 atm)
Density: d 2.83; d25.2 2.711
Derivative Type: Precipitated calcium carbonate
Additional Names: Precipitated chalk
Trademarks: Aeromatt; Albacar; Purecal (Wyandotte)
Properties: Commercial CaCO3 produced by chemical means. It is 98-99% pure. The byproduct process, the carbonation process, and the calcium chloride process of manuf from limestone are outlined in Kirk-Othmer Encyclopedia of Chemical Technology vol. 4 (Interscience, New York, 2nd ed., 1964) pp 7-11. Review: Woerner in Pigment Handbook vol. 1, T. C. Patton, Ed. (John Wiley, New York, 1973) pp 119-128.
Derivative Type: Prepared calcium carbonate
Additional Names: Drop chalk; prepared chalk; whiting; English white; Paris white
Properties: Native CaCO3 purified by elutriation.
CAUTION: Potential symptoms of overexposure are irritation of eyes, skin, respiratory system; cough. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 46.
Use: Manuf of paint, rubber, plastics, paper, dentifrices, ceramics, putty, polishes, insecticides, inks, shoe dressings; as a filler in production of adhesives, matches, pencils; crayons, linoleum, insulating compds, welding rods. In foods, cosmetics, pharmaceuticals, antibiotics; removing acidity of wines. In anal. chem for detecting and determining halogens in organic combinations; with NH4Cl for decomposing silicates; preparing CaCl2 soln for standardizing soap solns; for water analyses.
Therap-Cat: Antacid. Calcium supplement.
Therap-Cat-Vet: Antacid, calcium supplement, antidiarrheal agent.
Keywords: Antacid; Replenishers/Supplements; Calcium.
Calcium Chlorate Calcium Chloride Calcium Chromate(VI) Calcium Citrate Calcium Cyanamide

Calcium carbonate
Calcium carbonate.png Calcium-carbonate-xtal-3D-vdW.png
Calcium carbonate.jpg
CAS number 471-34-1 YesY
PubChem 10112
ChemSpider 9708 YesY
EC number 207-439-9
KEGG D00932 YesY
RTECS number FF9335000
ATC code A02AC01,A12AA04
Jmol-3D images Image 1
Image 2
Molecular formula 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)
Melting point 825 °C (aragonite)
1339 °C (calcite)[2]
Boiling point decomposes
Solubility in water 0.0013 g/100 mL (25°C)[3]
Solubility product, Ksp 4.8×10−9[1]
Solubility in dilute acids soluble
Acidity (pKa) 9.0
Refractive index (nD) 1.59
Crystal structure Trigonal
Space group 32/m
Std molar
entropy So298
93 J·mol−1·K−1[4]
Std enthalpy of
formation ΔfHo298
−1207 kJ·mol−1[4]
EU Index Not listed
NFPA 704
NFPA 704.svg
Flash point 825 °C; 1,517 °F; 1,098 K
LD50 6450 mg/kg (oral, rat)
Related compounds
Other anions Calcium bicarbonate
Other cations Magnesium carbonate
Strontium carbonate
Barium carbonate
Related compounds Calcium sulfate
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
Crystal structure of calcite

Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime, and is created when Ca ions in hard water react with carbonate ions creating limescale. It is commonly used medicinally as a calcium supplement or as an antacid, but excessive consumption can be hazardous.