Magnesium Hydroxide

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  • Identifiers

    CAS number
    1309-42-8

    Molecular formula
    H2MgO2

    SMILES
    [OH-].[OH-].[Mg+2]

    Safety labels

  • Odor profile

    Odor impact est.
    Low

  • Properties

    pKa est.
    -1.37 (strong acid)

    Molecular weight
    58.32 g/mol

    Melting point expt.

    • 350 °C (decomposes)

    Flash point

    • 48.44 ˚C est.

    Solubility expt.

    • Practically insoluble in water and in ethanol
    • White, friable masses or bulky, white powder; at about 700 °C is converted to MgO; sol in about 3,300 parts CO2-free water; more sol in water containing CO2; sol in dilute acids with effervescence; insol in alcohol /Magnesium carbonate hydroxide/
    • Soluble in dilute acids
    • 0.0009 G SOL IN 100 CC WATER @ 18 °C; 0.004 G SOL IN 100 CC WATER @ 100 °C; SOL IN AMMONIUM SALTS
    • Almost insoluble in alcohol

  • Synonyms

    • MAGNESIUM HYDROXIDE
    • 1309-42-8
    • Milk of magnesia
    • Magnesium dihydroxide
    • Magnesium hydrate
    • Magnesium hydroxide (Mg(OH)2)
    • Magnesium(II) hydroxide
    • Phillips magnesia tablets
    • Magnesium (as hydroxide)
    • Magnesii hydroxidum
    • INS NO.528
    • DTXSID4049662
    • Phillips milk of magnesia liquid
    • INS-528
    • NBZ3QY004S
    • CHEBI:6637
    • E-528
    • Hydrate, Magnesium
    • 215-170-3
    • Hydroxide, Magnesium
    • Magmex
    • Dulcolax Liquid
    • Gentle Laxative
    • MagLax
    • Magmilax Powder
    • Antacid-Laxative
    • MVT Powder
    • Walgreens Childrens
    • LAXADE
    • MAGNALAX
    • MiraFAST soft chews
    • CVS Health Childrens
    • Milk Of Magnesia Mint
    • RefChem:5971
    • Humco Milk Of Magnesia
    • Milk Of Magnesia Cherry
    • Milk Of Magnesia Liquid
    • Sunmark Milk Of Magnesia
    • Medibest Milk of Magnesia
    • Milk Of Magnesia Original
    • Milk of Magnesia Concentrate
    • Childrens Oral Saline Laxative
    • Dulcolax Soft Chews Watermelon
    • Sunmark Milk Of Magnesia Mint
    • Premier Value Milk of Magnesia
    • Equate Kids Gentle Laxative SC
    • CareOne Milk of Magnesia Cherry
    • DTXCID1029621
    • Dulcolax Soft Chews Mixed Berry
    • CHEBI:35149
    • Equate Gentle Laxative Soft chew
    • Careone Milk of magnesia Original
    • Phillips Original Milk Of Magnesia
    • Walgreens Childrens Saline Laxative
    • CVS Health Childrens Saline Laxative
    • Dulcolax Chewy Bites Assorted Fruits
    • Phillips Fresh Mint Milk Of Magnesia
    • CVS Magnesium Hydroxide Laxative Chew
    • Phillips Milk Of Magnesia Wild Cherry
    • Dulcolax Chewy Fruit Bites Cherry Berry
    • SUNMARK MILK OF MAGNESIA ORIGINAL
    • Walgreens Blueberry Raspberry Gentle Laxative
    • Meijer Magnesium Hydroxide Laxative Soft Chew
    • Careone Milk of magnesia Original Milk of Magnesia Original
    • Alcanex NHC 25
    • Baschem 12
    • Caustic magnesite
    • Combustrol 500
    • DP 393
    • DSB 100
    • Duhor
    • Duhor N
    • Ebson RF
    • FloMag H
    • FloMag HUS
    • Hydrofy G 1.5
    • Hydrofy G 2.5
    • Hydrofy N
    • Kisuma 4AF
    • Kisuma 5
    • Kisuma 5A
    • Kisuma 5B
    • Kisuma 5BG
    • Kisuma 5E
    • Kisuma 78
    • Kisuma S 4
    • KX 8S(A)
    • KX 8S(B)
    • Kyowamag F
    • Lycal 96 HSE
    • Mag Chem MH 10
    • MagneClear 58
    • Magnesia Magma
    • Magnesiamaito
    • Magnesium hydroxide gel
    • Magnesium oxide (Mg(OH)2)
    • Magnifin H 10
    • Marinco H
    • Marinco H 1241
    • Martinal VPF 8812
    • Reachim
    • S/G 84
    • Star 200
    • Versamag
    • Magnesiumhydroxide
    • 1909-42-8
    • Oxaine M
    • Magnesium hydroxide [JAN]
    • Magnesiumhydroxid
    • MgO2
    • magnesium(2+) hydroxide
    • Mg(OH)2
    • SCHEMBL9173
    • CHEMBL1200718
    • MAGNESIUM HYDROXIDE [II]
    • MAGNESIUM HYDROXIDE [MI]
    • MAGNESIUM HYDROXIDE [FCC]
    • MAGNESIUM HYDROXIDE [HSDB]
    • MAGNESIUM HYDROXIDE [VANDF]
    • MAGNESIUM HYDROXIDE [MART.]
    • MAGNESIUM HYDROXIDE [USP-RS]
    • MAGNESIUM HYDROXIDE [WHO-DD]
    • AKOS015904092
    • DB09104
    • PHENOL,2-[4,6-BIS(2,4-DIMETHYLPHENYL)-1,3,5-TRIAZIN-2-YL]-5-(2-BUTEN-1-YLOXY)-
    • MAGNESIUM HYDROXIDE [EP IMPURITY]
    • MAGNESIUM HYDROXIDE [ORANGE BOOK]
    • 1309-42-8

  • Applications

    Magnesium Hydroxide (CAS 1309-42-8) is widely used in pharmaceuticals as an antacid and laxative (milk of magnesia). In materials and plastics, it serves as a halogen-free flame retardant and smoke suppressant for polymers such as plastics, rubbers, coatings, and cables, and it also acts as a heat stabilizer for PVC and other polymers. It is used as a base/alkaline additive or pH-adjusting agent in chemical processing and cleaning formulations. In coatings and inks, Magnesium Hydroxide also functions as a filler and processing aid to improve handling and performance of the finished film.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 146.31
    methanol 314.16
    isopropanol 106.52
    water 325.2
    ethyl acetate 17.09
    n-propanol 85.61
    acetone 76.03
    n-butanol 57.22
    acetonitrile 47.55
    DMF 682.56
    toluene 2.46
    isobutanol 52.02
    1,4-dioxane 72.04
    methyl acetate 33.54
    THF 72.57
    2-butanone 32.06
    n-pentanol 28.56
    sec-butanol 56.76
    n-hexane 1.43
    ethylene glycol 243.16
    NMP 181.13
    cyclohexane 2.02
    DMSO 355.37
    n-butyl acetate 7.58
    n-octanol 11.88
    chloroform 6.37
    n-propyl acetate 9.68
    acetic acid 166.51
    dichloromethane 10.5
    cyclohexanone 25.62
    propylene glycol 148.59
    isopropyl acetate 9.45
    DMAc 285.27
    2-ethoxyethanol 86.83
    isopentanol 37.76
    n-heptane 1.67
    ethyl formate 34.71
    1,2-dichloroethane 11.6
    n-hexanol 17.75
    2-methoxyethanol 212.21
    isobutyl acetate 4.94
    tetrachloromethane 2.35
    n-pentyl acetate 6.95
    transcutol 77.4
    n-heptanol 11.79
    ethylbenzene 1.65
    MIBK 11.69
    2-propoxyethanol 48.81
    tert-butanol 116.03
    MTBE 29.33
    2-butoxyethanol 30.22
    propionic acid 83.43
    o-xylene 3.87
    formic acid 288.34
    diethyl ether 21.05
    m-xylene 2.79
    p-xylene 2.21
    chlorobenzene 3.33
    dimethyl carbonate 30.6
    n-octane 0.75
    formamide 249.41
    cyclopentanone 41.1
    2-pentanone 20.8
    anisole 9.99
    cyclopentyl methyl ether 20.01
    gamma-butyrolactone 62.0
    1-methoxy-2-propanol 117.5
    pyridine 23.75
    3-pentanone 15.35
    furfural 58.53
    n-dodecane 0.77
    diethylene glycol 84.16
    diisopropyl ether 5.04
    tert-amyl alcohol 65.23
    acetylacetone 21.36
    n-hexadecane 0.78
    acetophenone 9.52
    methyl propionate 28.9
    isopentyl acetate 6.08
    trichloroethylene 12.1
    n-nonanol 9.94
    cyclohexanol 28.72
    benzyl alcohol 15.19
    2-ethylhexanol 7.28
    isooctanol 8.27
    dipropyl ether 8.74
    1,2-dichlorobenzene 3.75
    ethyl lactate 15.81
    propylene carbonate 23.06
    n-methylformamide 241.63
    2-pentanol 28.91
    n-pentane 2.69
    1-propoxy-2-propanol 29.29
    1-methoxy-2-propyl acetate 12.82
    2-(2-methoxypropoxy) propanol 26.85
    mesitylene 2.65
    ε-caprolactone 24.69
    p-cymene 2.29
    epichlorohydrin 40.79
    1,1,1-trichloroethane 4.45
    2-aminoethanol 212.07
    morpholine-4-carbaldehyde 170.82
    sulfolane 83.6
    2,2,4-trimethylpentane 1.73
    2-methyltetrahydrofuran 32.92
    n-hexyl acetate 9.78
    isooctane 1.22
    2-(2-butoxyethoxy)ethanol 36.31
    sec-butyl acetate 5.09
    tert-butyl acetate 10.92
    decalin 0.9
    glycerin 212.77
    diglyme 64.58
    acrylic acid 100.38
    isopropyl myristate 4.38
    n-butyric acid 47.75
    acetyl acetate 8.71
    di(2-ethylhexyl) phthalate 6.93
    ethyl propionate 10.05
    nitromethane 164.33
    1,2-diethoxyethane 13.84
    benzonitrile 9.83
    trioctyl phosphate 5.87
    1-bromopropane 5.33
    gamma-valerolactone 73.7
    n-decanol 7.82
    triethyl phosphate 5.71
    4-methyl-2-pentanol 14.14
    propionitrile 29.22
    vinylene carbonate 25.64
    1,1,2-trichlorotrifluoroethane 60.28
    DMS 10.77
    cumene 1.8
    2-octanol 7.42
    2-hexanone 10.18
    octyl acetate 6.84
    limonene 3.89
    1,2-dimethoxyethane 99.84
    ethyl orthosilicate 5.4
    tributyl phosphate 5.77
    diacetone alcohol 30.72
    N,N-dimethylaniline 11.83
    acrylonitrile 49.14
    aniline 13.92
    1,3-propanediol 152.86
    bromobenzene 1.79
    dibromomethane 5.31
    1,1,2,2-tetrachloroethane 11.81
    2-methyl-cyclohexyl acetate 5.4
    tetrabutyl urea 10.88
    diisobutyl methanol 5.3
    2-phenylethanol 9.81
    styrene 2.26
    dioctyl adipate 7.78
    dimethyl sulfate 55.72
    ethyl butyrate 7.16
    methyl lactate 46.25
    butyl lactate 11.27
    diethyl carbonate 5.57
    propanediol butyl ether 35.22
    triethyl orthoformate 6.86
    p-tert-butyltoluene 2.5
    methyl 4-tert-butylbenzoate 14.7
    morpholine 102.39
    tert-butylamine 50.48
    n-dodecanol 6.26
    dimethoxymethane 122.53
    ethylene carbonate 20.78
    cyrene 27.2
    2-ethoxyethyl acetate 11.33
    2-ethylhexyl acetate 4.46
    1,2,4-trichlorobenzene 4.73
    4-methylpyridine 19.63
    dibutyl ether 5.84
    2,6-dimethyl-4-heptanol 5.3
    DEF 62.4
    dimethyl isosorbide 25.49
    tetrachloroethylene 9.86
    eugenol 18.86
    triacetin 12.01
    span 80 22.18
    1,4-butanediol 67.36
    1,1-dichloroethane 7.2
    2-methyl-1-pentanol 18.48
    methyl formate 141.0
    2-methyl-1-butanol 35.71
    n-decane 1.04
    butyronitrile 22.86
    3,7-dimethyl-1-octanol 8.34
    1-chlorooctane 2.84
    1-chlorotetradecane 1.58
    n-nonane 0.99
    undecane 0.87
    tert-butylcyclohexane 0.97
    cyclooctane 0.85
    cyclopentanol 45.22
    tetrahydropyran 30.87
    tert-amyl methyl ether 20.7
    2,5,8-trioxanonane 47.75
    1-hexene 3.55
    2-isopropoxyethanol 39.18
    2,2,2-trifluoroethanol 79.99
    methyl butyrate 16.21

    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