Calcium carbonate

Athanor · official

CCaO₃ · 100.09 g/mol

Also called limestone, calcite, chalk, E170

Inorganic

Open in Athanor

Drawn from its SMILES with RDKit

Names and identifiers

IUPAC name: calcium carbonate
Synonyms: limestone, calcite, chalk
+ 39 more
E170, Aeromatt, Calcium carbonate (1:1), Carbonic acid calcium salt (1:1), Calofort U, Albaglos, Aragonite, Calcicoll, Calseeds, Caltrate, Calwhite, Chemcarb, Duramite, Hydrocarb, Kotamite, Microcarb, Micromya, Neoanticid, Akadama, Albacar, Albafil, Atomite, Calmos, Calmote, Caltec, Carbium, Clefnon, Dacote, Marfil, Precipitated calcium carbonate, Allied whiting, Levigated chalk, Tums, Marble white, Marble dust, Camel-carb, Camel-tex, Camel-wite, Calofort S
Molecular formula: CCaO₃
Empirical formula: CCaO₃
Molecular weight: 100.09 g/mol
Exact mass: 99.94733
CAS number: 471-34-1
PubChem CID: 10112
Canonical SMILES: C(=O)([O-])[O-].[Ca+2]
Isomeric SMILES: C(=O)([O-])[O-].[Ca+2]
InChI: InChI=1S/CH2O3.Ca/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2
InChIKey: VTYYLEPIZMXCLO-UHFFFAOYSA-L
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Calcium carbonate appears as white, odorless powder or colorless crystals. Practically insoluble in water. Occurs extensive in rocks world-wide. Ground calcium carbonate (CAS: 1317-65-3) results directly from the mining of limestone. The extraction process keeps the carbonate very close to its original state of purity and delivers a finely ground product either in dry or slurry form. Precipitated calcium carbonate (CAS: 471-34-1) is produced industrially by the decomposition of limestone to calcium oxide followed by subsequent recarbonization or as a by-product of the Solvay process (which is[1]
5 values
From CAMEO Chemicals, the most authoritative source here.
Value As written Source
–shown Calcium carbonate appears as white, odorless powder or colorless crystals. Practically insoluble in water. Occurs extensive in rocks world-wide. Ground calcium carbonate (CAS: 1317-65-3) results directly from the mining of limestone. The extraction process keeps the carbonate very close to its original state of purity and delivers a finely ground product either in dry or slurry form. Precipitated calcium carbonate (CAS: 471-34-1) is produced industrially by the decomposition of limestone to calcium oxide followed by subsequent recarbonization or as a by-product of the Solvay process (which is [1] CAMEO Chemicals
– Dry Powder; Large Crystals; Liquid; Wet Solid; Other Solid; Wet Solid; Other Solid; Dry Powder; Wet Solid; Other Solid; Large Crystals; CBI; Dry Powder; Wet Solid; Dry Powder; Large Crystals; Wet Solid; Other Solid; Liquid; Dry Powder; Liquid; Liquid; Other Solid [2] EPA Chemical Data Reporting (CDR)
– WHITE POWDER OR PELLETS. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– White, odorless powder or colorless crystals. Calcium carbonate is soluble in concentrated mineral acids. [4] Occupational Safety and Health Administration (OSHA)
– White, odorless powder or colorless crystals. [5] The National Institute for Occupational Safety and Health (NIOSH)
Melting point: 825 to 1339 °C (1517 to 2442 °F) (Decomposes) (NIOSH, 2024)[1]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
825 to 1339 °Cshown 1517 to 2442 °F (Decomposes) (NIOSH, 2024) [1] CAMEO Chemicals
825 to 1339 °C 1517-2442 °F (decomposes) [4] Occupational Safety and Health Administration (OSHA)
825 to 1339 °C 1517-2442 °F (Decomposes) [5] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point: Reported, but no value passed the checks.
The value and why
Decomposes (NIOSH, 2024) (could not be read; source [1])
Density: 2.7 to 2.95 (NIOSH, 2024)[1]
5 values
3 of 5 sources agree on it (most common value).
Value As written Source
–shown 2.7 to 2.95 (NIOSH, 2024) [1] CAMEO Chemicals
– 2.8 g/cm³ [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 2.7-2.95 [4] Occupational Safety and Health Administration (OSHA)
– 2.93 @25 °C [7] PAC Chemical Database, U.S. Department of Energy
– 2.7-2.95 [5] The National Institute for Occupational Safety and Health (NIOSH)
2 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Solubility in water: Solubility in water, mg/l at 25 °C: 14 (very poor)[3]
7 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– 0.001 % (NIOSH, 2024) [1] CAMEO Chemicals
– ALKALI HYDROXIDE REDUCES ITS SOLUBILITY [6] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 733
– INSOL IN ALCOHOL [6] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 733
– SOLUBILITY IN H2O INCR BY AMMONIUM SALT & BY CO2 [6] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 733
– For more Solubility (Complete) data for CALCIUM CARBONATE (6 total), please visit the HSDB record page. [6] Hazardous Substances Data Bank (HSDB)
–shown Solubility in water, mg/l at 25 °C: 14 (very poor) [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 0.001% [5] The National Institute for Occupational Safety and Health (NIOSH)
Vapor pressure: Reported, but no value passed the checks.
The 3 values and why
0 mmHg (approx) (NIOSH, 2024) (no temperature given; source [1])
0 mmHg (approx) (no temperature given; source [4])
0 mmHg (approx) (no temperature given; source [5])

Value	As written	Source
–shown	Calcium carbonate appears as white, odorless powder or colorless crystals. Practically insoluble in water. Occurs extensive in rocks world-wide. Ground calcium carbonate (CAS: 1317-65-3) results directly from the mining of limestone. The extraction process keeps the carbonate very close to its original state of purity and delivers a finely ground product either in dry or slurry form. Precipitated calcium carbonate (CAS: 471-34-1) is produced industrially by the decomposition of limestone to calcium oxide followed by subsequent recarbonization or as a by-product of the Solvay process (which is	[1] CAMEO Chemicals
–	Dry Powder; Large Crystals; Liquid; Wet Solid; Other Solid; Wet Solid; Other Solid; Dry Powder; Wet Solid; Other Solid; Large Crystals; CBI; Dry Powder; Wet Solid; Dry Powder; Large Crystals; Wet Solid; Other Solid; Liquid; Dry Powder; Liquid; Liquid; Other Solid	[2] EPA Chemical Data Reporting (CDR)
–	WHITE POWDER OR PELLETS.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	White, odorless powder or colorless crystals. Calcium carbonate is soluble in concentrated mineral acids.	[4] Occupational Safety and Health Administration (OSHA)
–	White, odorless powder or colorless crystals.	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
825 to 1339 °Cshown	1517 to 2442 °F (Decomposes) (NIOSH, 2024)	[1] CAMEO Chemicals
825 to 1339 °C	1517-2442 °F (decomposes)	[4] Occupational Safety and Health Administration (OSHA)
825 to 1339 °C	1517-2442 °F (Decomposes)	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–shown	2.7 to 2.95 (NIOSH, 2024)	[1] CAMEO Chemicals
–	2.8 g/cm³	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	2.7-2.95	[4] Occupational Safety and Health Administration (OSHA)
–	2.93 @25 °C	[7] PAC Chemical Database, U.S. Department of Energy
–	2.7-2.95	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	0.001 % (NIOSH, 2024)	[1] CAMEO Chemicals
–	ALKALI HYDROXIDE REDUCES ITS SOLUBILITY	[6] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 733
–	INSOL IN ALCOHOL	[6] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 733
–	SOLUBILITY IN H2O INCR BY AMMONIUM SALT & BY CO2	[6] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 733
–	For more Solubility (Complete) data for CALCIUM CARBONATE (6 total), please visit the HSDB record page.	[6] Hazardous Substances Data Bank (HSDB)
–shown	Solubility in water, mg/l at 25 °C: 14 (very poor)	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	0.001%	[5] The National Institute for Occupational Safety and Health (NIOSH)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 5
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 0
H-bond acceptors: 3
Rotatable bonds: 0
TPSA (Å²): 63.2
Formal charge: 0
Complexity: 18 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: D3h of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C12.00%
Ca40.04%
O47.96%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: -2.83 Crippen (Wildman and Crippen 1999)
log S (water solubility): 1.32 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 4.65 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 100.09
log P ≤ 5 (Crippen): -2.83
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 3

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

This chemical does not meet GHS hazard criteria for 100% (12 of 12) of all reports.[8]

Exposure limits

PEL-TWA (8-Hour Time Weighted Average): 15 mg/m³ (total dust), 5 mg/m³ (respirable fraction)[4]
PEL: TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp)[5]
REL-TWA (Time Weighted Average): 10 mg/m³ (total dust), 5 mg/m³ (respirable fraction)[4]
REL: TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)[5]
TLV-TWA (Time Weighted Average): Withdrawn [2007] - Insufficient data.[4]
IDLH: N.D. See: IDLH index[5]

First aid

Excerpt from NIOSH Pocket Guide for Calcium carbonate: Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: SOAP WASH - If this chemical contacts the skin, wash the contaminated skin with soap and water. Breathing: Fresh AIR - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. Other measures are usually unnecessary. (NIOSH, 2024)[1]
(General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Soap wash - If this chemical contacts the skin, wash the contaminated skin with soap and water. Breathing: Fresh air[5]
Fresh air.[3]
Rinse skin with plenty of water or shower.[3]

Storage

Separated from acids, aluminium, ammonium salts, fluorine and magnesium.[3]
Separated from acids, aluminium and ammonium salts.[6]

Incompatibilities

Calcium carbonate ... Ignite and burn fiercely in contact with fluorine. (fluorine: Metal salts)[6]
When a mixture of magnesium and calcium carbonate is heated in a current of hydrogen, a violent explosion occurs. (magnesium: Hydrogen and calcium carbonate)[6]
Calcium carbonate reacts with acids with evolution of carbon dioxide and heat (reported to be about 19 kJ/mol in hydrochloric acid).[6]
Acids, alum, ammonium salts, mercury & hydrogen, fluorine, magnesium.[6]

Safety data sheets on the supplier’s page: Ambeed, Aladdin Scientific, Thermo Fisher Scientific.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[5]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
[6]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[7]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[8]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[9]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.