Etidronic acid
A 1,1-bis(phosphonic acid) that is (ethane-1,1-diyl)bis(phosphonic acid) having a hydroxy substituent at the 1-position. It inhibits the formation, growth, and dissolution of hydroxyapatite crystals by chemisorption to calcium phosphate surfaces. — ChEBI
Safety documents & references
1 indexed referencesFind 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 number | 2809-21-4 | ChEBI ↗ |
| Molecular formula | C2H8O7P2 | ChEBI ↗ |
| Molar mass | 206.027 g/mol | ChEBI ↗ |
| Monoisotopic mass | 205.97453 Da | ChEBI ↗ |
| Formal charge | 0 | ChEBI ↗ |
| ChEBI identifier | CHEBI:4907 | ChEBI ↗ |
Cross-source molecular data
PubChem| Molar mass | 206.03 g/mol | PubChem ↗ |
| Exact mass | 205.97452659 Da | PubChem ↗ |
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 identifieretidronic acid(1-hydroxyethane-1,1-diyl)bis(phosphonic acid)DBVJJBKOTRCVKF-UHFFFAOYSA-NCC(O)(P(=O)(O)O)P(=O)(O)OInChI=1S/C2H8O7P2/c1-2(3,10(4,5)6)11(7,8)9/h3H,1H3,(H2,4,5,6)(H2,7,8,9)Names & synonyms
Names are supplied by ChEBI. Trade names and related synonyms may describe a broader product context.
Classification & relationships
ChEBI ontologyRoles recorded in ChEBI
Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.
Safety classification · Japan
NITE / Japanese government1-Hydroxyethane-1,1-diylbis(phosphonic acid) · 24A6139
| Endpoint | Reported classification |
|---|---|
| Acute toxicity （Oral） | Category 4 |
| Skin corrosion/irritation | Category 1 |
| Serious eye damage/eye irritation | Category 1 |
| Specific target organ toxicity - Single exposure | Category 2 (systemic toxicity) |
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 classificationMass ↔ amount of substance
Calculated from sourced massUses 206.027 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.
Elemental composition
Theoretical mass fractionsOPCHCalculated 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 associationsSources & record history
Checked 27 Sep 2026Release 255, 9 September 2026. ChEBI three-star (manually annotated) source entry. View original record ↗ · CC BY 4.0
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.