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Salts and minerals

Calcium carbonate vs calcium hydroxide

Calcium carbonate (CCaO3, CAS 471-34-1) and calcium hydroxide (H2CaO2, CAS 1305-62-0) are both listed under pH adjusters and neutralizers.

Calcium carbonate has a molar mass of 100.09 g/mol, calcium hydroxide 74.09 g/mol.

Measured melting points are 825 to 1338.9 for calcium carbonate and 580 °C for calcium hydroxide.

Calcium hydroxide carries the GHS signal word Danger, while no signal word is recorded for calcium carbonate in our records.

On CompoundList, 746 suppliers list calcium carbonate and 496 suppliers list calcium hydroxide.

Data last updated 7 October 2026

Calcium carbonate and calcium hydroxide compared side by side
Calcium carbonate chemical structure, CCaO3, CAS 471-34-1
Calcium carbonate
Calcium hydroxide chemical structure, H2CaO2, CAS 1305-62-0
Calcium hydroxide
Identity
Name in our databaseCalcium carbonateCalcium hydroxide
CAS number471-34-11305-62-0
Molecular formulaCCaO3H2CaO2
Molar mass100.09 g/mol74.09 g/mol
IUPAC namecalcium carbonatecalcium dihydroxide
EC number207-439-9215-137-3
Physical properties
AppearanceWhite hexagonal crystals or powder (Calcite), white orthrombic crystals or powder (Argonite), colorless hexagonalCrystals or soft granules or powder
Melting point825 to 1338.9580 °C
Boiling pointDecomposesDecomposes
Density2.8 g/cm³Approximately 2.2 g/cm³
Flash pointNot recorded/Calcium Hydroxide is/ non flammable
SolubilityPractically insoluble in water, soluble in dilute acidsSolubility in water is decreased by the presence of fixed alkali hydroxides.
LogP (octanol/water)Computed from the structure-2.83-0.73
Safety (GHS)
Signal wordNoneDanger
PictogramsNone
GHS05: Corrosive
GHS07: Harmful or irritant
Hazard statementsNo hazard statements recorded
  • H314 Causes severe skin burns and eye damage.
  • H315 Causes skin irritation.
  • H318 Causes serious eye damage.
  • H335 May cause respiratory irritation.
Uses and classification
Uses and functions
  • Colorants
  • Fertilizers and micronutrients
  • Food colors
  • Fillers and thixotropes
  • PH adjusters
  • Additive
  • Acidulants and acidity regulators
  • Astringent
  • Pharmaceutical
  • Buffering
CategoryInorganic chemicals › Carbonates and bicarbonatesInorganic chemicals › Hydroxides and bases
HS code283650Calcium carbonate282590Hydrazine and hydroxylamine and their inorganic salts, other inorganic bases, other…
Market on CompoundList
Suppliers746 suppliers496 suppliers
Supplier countries71 countries, most in India, United States, China55 countries, most in India, United States, China
Price rangeOnly prices set by suppliers who manage their own profilePrice on requestPrice on request

Measured and computed values as shown on each chemical page, plus live listings on CompoundList. Details may have changed, please confirm them with the supplier. Safety data is a summary, not an SDS.

Calcium carbonate
Calcium hydroxide

More comparisons

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