Etidronic Acid

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  • Identifiers

    CAS number
    2809-21-4

    Molecular formula
    C2H8O7P2

    SMILES
    CC(O)(P(=O)(O)O)P(=O)(O)O

    Safety labels

    Corrosive
    Corrosive

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 75.8%
    Sour 21.02%
    Savory 17.81%
    Sharp 17.74%
    Sulfurous 17.44%
    Clean 16.93%
    Sweet 15.22%
    Burnt 14.83%
    Caramellic 14.5%
    Milky 13.97%

     

    Flavor
    Odorless 68.66%
    Sour 32.55%
    Bland 26.7%
    Very mild 25.87%
    Mild 24.87%
    Yeast 20.79%
    Acidic 20.65%
    Sweet-like 20.21%
    Soy 19.59%
    Vinegar 19.55%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    -3.7

    pKa est.
    7.74 (neutral)

    Molecular weight
    206.03 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Melting point expt.

    • 198-199

    Boiling point

    • 578.8

    Flash point

    • 273.53 ˚C est.

    Solubility expt.

    • 1.15e+01 g/L

  • Synonyms

    • Etidronic acid
    • 2809-21-4
    • 1-Hydroxyethylidene-1,1-diphosphonic acid
    • HEDP
    • EHDP
    • Etidronsaeure
    • Turpinal SL
    • Acetodiphosphonic acid
    • Hydroxyethanediphosphonic acid
    • Acido etidronico
    • Oxyethylidenediphosphonic acid
    • Acide etidronique
    • Dequest 2015
    • Dequest Z 010
    • Ferrofos 510
    • Phosphonic acid, (1-hydroxyethylidene)bis-
    • Dequest 2010
    • 1-Hydroxyethane-1,1-diphosphonic acid
    • Diphosphonate (base)
    • 1-Hydroxyethanediphosphonic acid
    • (1-Hydroxyethylidene)diphosphonic acid
    • 1-Hydroxyethane-1,1-bisphosphonic acid
    • (Hydroxyethylidene)diphosphonic acid
    • Ethane-1-hydroxy-1,1-diphosphonic acid
    • Acidum etidronicum
    • (1-Hydroxyethylidene)bisphosphonic acid
    • 1-HYDROXY-1,1-DIPHOSPHONOETHANE
    • (1-Hydroxyethylene)diphosphonic acid
    • (1-Hydroxyethylidene)bis(phosphonic acid)
    • (1-hydroxy-1-phosphonoethyl)phosphonic acid
    • Hydroxyethane-1,1-diphosphonic acid
    • 1000SL
    • RP 61
    • Phosphonic acid, (1-hydroxyethylidene)di-
    • M2F465ROXU
    • NSC-227995
    • ethane-1-hydroxy-1,1-bisphosphonic acid
    • DTXSID6023028
    • M05BA01
    • Phosphonic acid, P,P'-(1-hydroxyethylidene)bis-
    • 1-hydroxyethane 1,1-diphosphonic acid
    • (1-hydroxy-ethylidene)diphosphonic acid
    • CHEBI:4907
    • DTXCID103028
    • NSC227995
    • (1-Hydroxyethylidene)-1,1-diphosphonic acid
    • Xydiphone
    • Etidron
    • Xidiphon
    • Dicalcium EHDP
    • EHDP, Dicalcium
    • Hydroxyethylidene Diphosphonic Acid
    • Etidronate, Sodium
    • Etidronate, Disodium
    • HEDSPA
    • Etidronate, Dicalcium
    • RefChem:5819
    • Salt Etidronate, Tetrapotassium
    • V10BX03
    • Diphosphonic Acid, Hydroxyethylidene
    • 1-Hydroxyethylene Diphosphonate, Disodium
    • Diphosphonate, Disodium 1-Hydroxyethylene
    • (1-hydroxyethylene)diphosphonic acid, Tetrapotassium Salt
    • 220-552-8
    • etidronate
    • (1-Hydroxyethane-1,1-diyl)diphosphonic acid
    • 1-Hydroxyethane-1,1-diphosphonate
    • Ethane-1-hydroxy-1,1-diphosphonate
    • (1-hydroxyethane-1,1-diyl)bis(phosphonic acid)
    • Acide etidronique [INN-French]
    • Acido etidronico [INN-Spanish]
    • Acidum etidronicum [INN-Latin]
    • 1,1,1-Ethanetriol diphosphonate
    • 1-Hydroxyethylidene-1,1-bisphosphonate
    • MFCD00070585
    • (1-Hydroxyethylidene)diphoshonic acid
    • (1-hydroxy-1-phosphono-ethyl)phosphonic acid
    • C2H8O7P2
    • Etidronic Acid-d3
    • Etidronic Acid-d3 Sodium Salt
    • CHEMBL871
    • 2809-21-4 (freeacid)
    • (1-hydroxyethan-1,1-diyl)bis(phosphonic acid)
    • 774173-70-5
    • Etidronic acid [USAN:INN:BAN]
    • SMR000038750
    • 1-Hydroxyethylidene-1,1-biphosphonate
    • 358730-93-5
    • HSDB 5898
    • 1-Hydroxyethylidenediphosphonic acid
    • NCGC00159352-02
    • EINECS 220-552-8
    • Phosphonic acid, 1-hydroxy-1,1-ethanediyl ester
    • UNII-M2F465ROXU
    • NSC 227995
    • BRN 1789291
    • Etidronicacid
    • Etidronic acid (USAN/INN)
    • Xidiphone
    • etidronic-acid
    • Etidronate;
    • Ksidifon;
    • Ethane-1-hydroxy-1,1-bisphosphonate
    • HDEPA
    • OEDFK
    • OEDP
    • Etidronate (Didronel)
    • 1-HydroxyEthylidene-1,1-DiphosphonicAcid
    • Prestwick0_000863
    • Prestwick1_000863
    • Prestwick2_000863
    • Prestwick3_000863
    • ETIDRONATE [VANDF]
    • EC 220-552-8
    • (1-Hydroxy-1,1-ethanediyl)bis(phosphonic acid)
    • ETIDRONIC ACID [MI]
    • SCHEMBL18607
    • BSPBio_000905
    • ETIDRONIC ACID [INN]
    • 0-02-00-00171 (Beilstein Handbook Reference)
    • MLS002207267
    • MLS002695948
    • ETIDRONIC ACID [HSDB]
    • ETIDRONIC ACID [USAN]
    • SPBio_002826
    • BPBio1_000997
    • GTPL7184
    • 2809-21-4

  • Applications

    Etidronic acid is widely used as a chelating agent and scale/corrosion control additive across multiple industries. In industrial water treatment, it acts as a scale inhibitor and corrosion inhibitor for cooling water, boiler feeds, and process waters. In detergents and household cleaners, it sequesters metal ions to soften water and improve cleaning performance. In cosmetics and personal care, it serves as a chelating agent to stabilize formulations and extend product shelf life. In coatings and inks, it functions as a dispersant and metal ion stabilizer to improve pigment suspension and storage stability. In polymers and plastics processing, it can act as a stabilizer and chelating agent to reduce metal-catalyzed degradation during synthesis and processing.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 15.94
    methanol 53.22
    isopropanol 10.53
    water 589.46
    ethyl acetate 1.08
    n-propanol 7.74
    acetone 8.84
    n-butanol 6.85
    acetonitrile 1.12
    DMF 75.52
    toluene 0.76
    isobutanol 4.49
    1,4-dioxane 4.88
    methyl acetate 0.81
    THF 20.86
    2-butanone 2.43
    n-pentanol 3.45
    sec-butanol 5.05
    n-hexane 0.82
    ethylene glycol 55.6
    NMP 39.56
    cyclohexane 1.54
    DMSO 115.06
    n-butyl acetate 0.8
    n-octanol 2.9
    chloroform 0.33
    n-propyl acetate 0.71
    acetic acid 5.07
    dichloromethane 0.5
    cyclohexanone 4.06
    propylene glycol 27.88
    isopropyl acetate 1.73
    DMAc 29.24
    2-ethoxyethanol 21.87
    isopentanol 4.84
    n-heptane 1.77
    ethyl formate 1.62
    1,2-dichloroethane 0.76
    n-hexanol 4.35
    2-methoxyethanol 66.66
    isobutyl acetate 0.32
    tetrachloromethane 0.53
    n-pentyl acetate 1.09
    transcutol 13.12
    n-heptanol 4.66
    ethylbenzene 0.39
    MIBK 5.1
    2-propoxyethanol 19.64
    tert-butanol 14.01
    MTBE 2.63
    2-butoxyethanol 11.76
    propionic acid 2.17
    o-xylene 1.29
    formic acid 49.76
    diethyl ether 3.92
    m-xylene 1.21
    p-xylene 0.44
    chlorobenzene 0.16
    dimethyl carbonate 2.82
    n-octane 0.8
    formamide 69.49
    cyclopentanone 9.81
    2-pentanone 5.47
    anisole 0.92
    cyclopentyl methyl ether 8.61
    gamma-butyrolactone 6.32
    1-methoxy-2-propanol 52.22
    pyridine 1.5
    3-pentanone 2.99
    furfural 5.84
    n-dodecane 0.3
    diethylene glycol 38.65
    diisopropyl ether 2.34
    tert-amyl alcohol 7.13
    acetylacetone 6.18
    n-hexadecane 0.32
    acetophenone 1.26
    methyl propionate 2.25
    isopentyl acetate 0.74
    trichloroethylene 0.47
    n-nonanol 2.78
    cyclohexanol 5.09
    benzyl alcohol 1.57
    2-ethylhexanol 1.92
    isooctanol 3.02
    dipropyl ether 3.61
    1,2-dichlorobenzene 0.18
    ethyl lactate 2.83
    propylene carbonate 1.97
    n-methylformamide 23.17
    2-pentanol 6.1
    n-pentane 1.69
    1-propoxy-2-propanol 12.11
    1-methoxy-2-propyl acetate 3.16
    2-(2-methoxypropoxy) propanol 6.93
    mesitylene 1.47
    ε-caprolactone 2.31
    p-cymene 0.81
    epichlorohydrin 3.62
    1,1,1-trichloroethane 0.32
    2-aminoethanol 43.68
    morpholine-4-carbaldehyde 23.48
    sulfolane 26.68
    2,2,4-trimethylpentane 0.55
    2-methyltetrahydrofuran 4.9
    n-hexyl acetate 1.23
    isooctane 0.56
    2-(2-butoxyethoxy)ethanol 10.1
    sec-butyl acetate 0.62
    tert-butyl acetate 3.4
    decalin 0.36
    glycerin 81.39
    diglyme 16.59
    acrylic acid 2.65
    isopropyl myristate 0.72
    n-butyric acid 3.13
    acetyl acetate 0.68
    di(2-ethylhexyl) phthalate 0.83
    ethyl propionate 1.03
    nitromethane 6.06
    1,2-diethoxyethane 2.16
    benzonitrile 0.37
    trioctyl phosphate 1.06
    1-bromopropane 0.6
    gamma-valerolactone 12.31
    n-decanol 2.08
    triethyl phosphate 0.91
    4-methyl-2-pentanol 4.27
    propionitrile 0.81
    vinylene carbonate 1.02
    1,1,2-trichlorotrifluoroethane 7.94
    DMS 0.7
    cumene 0.47
    2-octanol 2.76
    2-hexanone 1.58
    octyl acetate 0.91
    limonene 1.49
    1,2-dimethoxyethane 15.7
    ethyl orthosilicate 1.12
    tributyl phosphate 0.67
    diacetone alcohol 14.47
    N,N-dimethylaniline 2.28
    acrylonitrile 1.04
    aniline 1.7
    1,3-propanediol 29.81
    bromobenzene 0.11
    dibromomethane 0.46
    1,1,2,2-tetrachloroethane 0.84
    2-methyl-cyclohexyl acetate 0.92
    tetrabutyl urea 2.04
    diisobutyl methanol 2.55
    2-phenylethanol 1.95
    styrene 0.28
    dioctyl adipate 0.7
    dimethyl sulfate 8.44
    ethyl butyrate 1.11
    methyl lactate 10.53
    butyl lactate 2.7
    diethyl carbonate 0.48
    propanediol butyl ether 10.73
    triethyl orthoformate 1.33
    p-tert-butyltoluene 1.12
    methyl 4-tert-butylbenzoate 4.36
    morpholine 8.57
    tert-butylamine 7.29
    n-dodecanol 1.49
    dimethoxymethane 43.21
    ethylene carbonate 1.0
    cyrene 11.35
    2-ethoxyethyl acetate 1.32
    2-ethylhexyl acetate 0.54
    1,2,4-trichlorobenzene 0.22
    4-methylpyridine 1.25
    dibutyl ether 1.22
    2,6-dimethyl-4-heptanol 2.55
    DEF 8.51
    dimethyl isosorbide 10.92
    tetrachloroethylene 1.0
    eugenol 5.55
    triacetin 1.36
    span 80 5.65
    1,4-butanediol 11.38
    1,1-dichloroethane 0.37
    2-methyl-1-pentanol 2.2
    methyl formate 11.41
    2-methyl-1-butanol 3.94
    n-decane 0.59
    butyronitrile 1.18
    3,7-dimethyl-1-octanol 1.78
    1-chlorooctane 0.72
    1-chlorotetradecane 0.34
    n-nonane 0.64
    undecane 0.4
    tert-butylcyclohexane 0.33
    cyclooctane 1.18
    cyclopentanol 8.35
    tetrahydropyran 2.89
    tert-amyl methyl ether 3.51
    2,5,8-trioxanonane 12.91
    1-hexene 0.83
    2-isopropoxyethanol 9.31
    2,2,2-trifluoroethanol 6.73
    methyl butyrate 1.41

    Scent© AI

1 4

IFRA standard 51

Recommendation
No restriction
Maximum acceptable concentrations in the finished product (%)
Category 1
Products applied to the lips
 No restriction Category 7A
Rinse-off products applied to the hair with some hand contact
 No restriction
Category 2
Products applied to the axillae
 No restriction Category 7B
Leave-on products applied to the hair with some hand contact
 No restriction
Category 3
Products applied to the face/body using fingertips
 No restriction Category 8
Products with significant anogenital exposure
 No restriction
Category 4
Products related to fine fragrance
 No restriction Category 9
Products with body and hand exposure, primarily rinse off
 No restriction
Category 5A
Body lotion products applied to the body using the hands (palms), primarily leave on
 No restriction Category 10A
Household care products with mostly hand contact
 No restriction
Category 5B
Face moisturizer products applied to the face using the hands (palms), primarily leave on
 No restriction Category 10B
Household care products with mostly hand contact, including aerosol/spray products (with potential leave-on skin contact)
 No restriction
Category 5C
Hand cream products applied to the hands using the hands (palms), primarily leave on
 No restriction Category 11A
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate without UV exposure
 No restriction
Category 5D
Baby Creams, baby Oils and baby talc
 No restriction Category 11B
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate with potential UV exposure
 No restriction
Category 6
Products with oral and lip exposure
 No restriction Category 12
Products not intended for direct skin contact, minimal or insignificant transfer to skin
 No restriction