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Chemical substance record

Calcium dihydroxide

1305-62-0Ca.2HO74.092 g/mol
MineralChEBI source record

Calcium dihydroxide is indexed in ChEBI under CHEBI:31341, with the reported formula Ca.2HO. Use the source record and structural identifiers below to confirm the material you need. — ChEBI

Safety references

Safety documents & references

2 indexed references
US · NIOSH

Occupational chemical safety guide

Calcium hydroxide

Read official guide
JP · NITE

Government GHS classification

H26-B-125 / - · FY2014

View classification

Find a product-specific SDS

Safety guides and government classification records are not a manufacturer’s SDS. Match supplier, product number, concentration, physical form, region and revision before using a document.

Identity & molecular properties

Source-linked values
CAS number1305-62-0ChEBI ↗
Molecular formulaCa.2HOChEBI ↗
Molar mass74.092 g/molChEBI ↗
Monoisotopic mass73.96807 DaChEBI ↗
Formal charge0ChEBI ↗
ChEBI identifierCHEBI:31341ChEBI ↗

Cross-source molecular data

PubChem
Molar mass74.09 g/molPubChem ↗
Exact mass73.9680702 DaPubChem ↗

PubChem computed values are shown separately from the ChEBI record. An exact InChIKey match was used to connect the records. Molecular descriptors do not describe a supplied product’s purity, particle size or performance.

Names & structural identifiers

Copy any identifier
calcium dihydroxide
calcium dihydroxide
AXCZMVOFGPJBDE-UHFFFAOYSA-L
[Ca+2].[OH-].[OH-]
InChI=1S/Ca.2H2O/h;2*1H2/q+2;;/p-2

Names & synonyms

calcium(2+) hydroxidecalcium(II) hydroxide

Names are supplied by ChEBI. Trade names and related synonyms may describe a broader product context.

Classification & relationships

ChEBI ontology

Roles recorded in ChEBI

astringent

Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.

Safety classification · Japan

NITE / Japanese government
Japan · FY2014 source classification
Calcium hydroxide · H26-B-125 / -
EndpointReported classification
Skin corrosion/irritationCategory 2
Serious eye damage/eye irritationCategory 1
Specific target organ toxicity - Single exposureCategory 1 (respiratory system)

Selected source-reported endpoints. Other endpoints, rationales and conditions remain in the original classification. Missing or unlisted information does not mean non-hazardous. This is not a global classification or transport decision.

Read the original NITE classification

Mass ↔ amount of substance

Calculated from sourced mass
Equivalent amount
0.0134967 mol

Uses 74.092 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.

Elemental composition

Theoretical mass fractions
Ca
Calcium · 2 atoms
82.50%
O
Oxygen · 1 atom
16.47%
H
Hydrogen · 1 atom
1.04%

Calculated theoretical mass fractions from the reported formula and PubChem periodic-table atomic masses. These are not assay or purity results.

Research & patent references

Selected source associations

Explore literature using this exact identifier.

Sources & record history

Checked 27 Sep 2026
EMBL-EBI ChEBI · CHEBI:31341

Release 255, 9 September 2026. ChEBI three-star (manually annotated) source entry. View original record ↗ · CC BY 4.0

NCBI PubChem · CID 14777 · retrieved 2026-09-27

PubCAS formats source data, connects references and computes explicitly labelled conversions. CAS cross-references are supplied by ChEBI; they do not constitute CAS verification or endorsement.