Osmium Tetroxide

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  • Identifiers

    CAS number
    20816-12-0

    Molecular formula
    O4Os

    SMILES
    O=[Os](=O)(=O)=O

    Safety labels

    Corrosive
    Corrosive

    Acute Toxic
    Acute Toxic

  • Odor profile

    Fragrance
    Odorless 87.05%
    Sour 19.88%
    Burnt 17.55%
    Sharp 17.33%
    Pungent 14.15%
    Clean 11.33%
    Ethereal 10.58%
    Caramellic 10.19%
    Sweet 9.23%
    Bitter 9.17%

     

    Odor threshold

    • Odor Threshold Low: 0.0019 [mmHg]. Odor threshold from NJ "Hazardous Substance Fact Sheet"
    • Air odor threshhold: 0.0019 ppm v/v. Water odor threshhold: 0.012 ppm w/v (amount in water that generates the air odor threshhold in a closed system).

  • Properties

    pKa est.
    -1.92 (strong acid)

    Molecular weight
    254.2 g/mol

    Melting point expt.

    • 105 °F (NIOSH, 2024)
    • 40.6 °C
    • 42 °C
    • 105 °F

    Boiling point

    • 266 °F at 760 mmHg (NIOSH, 2024)
    • 130.0 °C at 760 mm Hg; begins to sublime and distill well below bp
    • 130 °C
    • 266 °F

    Flash point

    • 111.18 ˚C est.

    Solubility expt.

    • 6 % at 77 °F (NIOSH, 2024)
    • Sol in benzene, alcohol, ether, ammonium hydroxide, and phosphorus oxychloride; solubility in carbon tetrachloride @ 25 deg: 375 g/100 g
    • Solubility (g/100 cc solvent): 5.70 g in water @ 10 °C; 6.23 g in water @ 25 °C; 250 +/- 10 g in carbon tetrachloride @ 20 °C
    • In water, 7.24 (g/100 g) at 25 °C
    • Solubility in water, g/100ml at 25 °C: 6
    • (77 °F): 6%

  • Synonyms

    • OSMIUM TETROXIDE
    • 20816-12-0
    • Osmium tetraoxide
    • Osmic acid
    • tetraoxoosmium
    • Perosmic oxide
    • Osmic acid anhydride
    • Osmium oxide (OsO4), (T-4)-
    • Perosmic acid anhydride
    • Osmium(VIII)-oxide
    • OsO4
    • Osmium oxide, (T-4)-
    • RCRA waste number P087
    • osmium(IV) oxide
    • MFCD00011150
    • Osmium(VIII)oxide
    • HSDB 719
    • P40W033BGM
    • EINECS 244-058-7
    • Osmium oxide (OsO4), (beta-4)-
    • UN2471
    • UNII-P40W033BGM
    • OSMIUM TETROXIDE [MI]
    • OSMIUM TETROXIDE [HSDB]
    • DTXSID5042245
    • CHEBI:88215
    • (T-4)-OSMIUM OXIDE (OSO4)
    • OSMIUM OXIDE (OSO4)
    • OSMIUM OXIDE [OSO4]
    • Osmium Tetroxide (4% in H2O)
    • Osmiumtetroxide
    • Acid, Osmic
    • Tetroxide, Osmium
    • OSMIUM OXIDE [OSO4], (T-4)-
    • RCRA waste no. P087
    • OSMIUM (VIII) OXIDE
    • osmiumtetroxid
    • osmiumtetraoxide
    • Osmium oxide (OsO4) (T-4)-
    • Osmium tetra oxide
    • osmium(VIII)tetraoxide
    • MILAS' REAGENT
    • Osmium(VIII)-tetroxide
    • REAGENTS, MILAS'
    • osmium (VIII) tetraoxide
    • Osmium oxide OsO4 (T-4)
    • DTXCID3022245
    • Osmium tetroxide (ACGIH:OSHA)
    • Osmium tetroxide, Sealed ampule.
    • OSMIUM OXIDE OSO4 (T-4)-
    • Osmium tetroxide, puriss., 99.9%
    • AKOS005267110
    • Osmium(VIII) oxide (99.95%-Os)
    • OSMIUM TETROXIDE (4% IN WATER)
    • Osmium tetroxide [UN2471] [Poison]
    • Osmium tetroxide, ACS reagent, >=98.0%
    • Osmium tetroxide, ReagentPlus(R), 99.8%
    • D91859
    • Q422021
    • Os EnCat(R) 40, extent of labeling: 0.3 mmol/g Os loading

  • Applications

    Osmium Tetroxide (CAS 20816-12-0) is widely used as an oxidant for syn-dihydroxylation of alkenes in organic synthesis, typically in catalytic OsO4 systems with a co-oxidant to generate vicinal diols; it also serves as a heavy-atom stain and contrast agent for transmission electron microscopy (TEM) and light microscopy, particularly highlighting lipid-rich membranes; in histology sample preparation it is used as a fixative and contrast-enhancing reagent; in organic synthesis it is employed for selective oxidations, supporting the preparation of pharmaceutical intermediates and materials.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 240.73
    methanol 308.93
    isopropanol 211.29
    water 74.57
    ethyl acetate 206.94
    n-propanol 169.58
    acetone 439.99
    n-butanol 156.13
    acetonitrile 253.83
    DMF 1044.02
    toluene 114.19
    isobutanol 121.6
    1,4-dioxane 342.38
    methyl acetate 223.78
    THF 529.9
    2-butanone 251.49
    n-pentanol 117.99
    sec-butanol 181.67
    n-hexane 60.53
    ethylene glycol 170.19
    NMP 694.86
    cyclohexane 81.16
    DMSO 1016.67
    n-butyl acetate 110.91
    n-octanol 113.39
    chloroform 318.72
    n-propyl acetate 128.08
    acetic acid 208.26
    dichloromethane 346.55
    cyclohexanone 227.61
    propylene glycol 126.85
    isopropyl acetate 161.97
    DMAc 801.3
    2-ethoxyethanol 258.12
    isopentanol 129.93
    n-heptane 61.45
    ethyl formate 167.75
    1,2-dichloroethane 281.54
    n-hexanol 120.28
    2-methoxyethanol 507.55
    isobutyl acetate 78.35
    tetrachloromethane 120.69
    n-pentyl acetate 112.82
    transcutol 299.46
    n-heptanol 98.2
    ethylbenzene 76.16
    MIBK 161.12
    2-propoxyethanol 242.95
    tert-butanol 274.17
    MTBE 238.98
    2-butoxyethanol 161.43
    propionic acid 136.75
    o-xylene 121.75
    formic acid 194.6
    diethyl ether 303.36
    m-xylene 109.7
    p-xylene 87.06
    chlorobenzene 112.02
    dimethyl carbonate 199.94
    n-octane 36.11
    formamide 338.42
    cyclopentanone 335.42
    2-pentanone 242.29
    anisole 171.73
    cyclopentyl methyl ether 279.57
    gamma-butyrolactone 333.83
    1-methoxy-2-propanol 397.84
    pyridine 225.72
    3-pentanone 219.87
    furfural 351.81
    n-dodecane 31.68
    diethylene glycol 271.51
    diisopropyl ether 134.06
    tert-amyl alcohol 211.7
    acetylacetone 286.51
    n-hexadecane 34.4
    acetophenone 170.5
    methyl propionate 231.04
    isopentyl acetate 97.89
    trichloroethylene 318.01
    n-nonanol 105.06
    cyclohexanol 163.55
    benzyl alcohol 126.33
    2-ethylhexanol 89.38
    isooctanol 80.29
    dipropyl ether 149.95
    1,2-dichlorobenzene 128.83
    ethyl lactate 112.47
    propylene carbonate 178.44
    n-methylformamide 365.35
    2-pentanol 155.27
    n-pentane 93.45
    1-propoxy-2-propanol 184.76
    1-methoxy-2-propyl acetate 151.18
    2-(2-methoxypropoxy) propanol 169.94
    mesitylene 94.37
    ε-caprolactone 191.12
    p-cymene 75.42
    epichlorohydrin 332.74
    1,1,1-trichloroethane 238.58
    2-aminoethanol 176.19
    morpholine-4-carbaldehyde 517.88
    sulfolane 538.53
    2,2,4-trimethylpentane 43.2
    2-methyltetrahydrofuran 305.89
    n-hexyl acetate 135.9
    isooctane 34.52
    2-(2-butoxyethoxy)ethanol 192.82
    sec-butyl acetate 95.09
    tert-butyl acetate 186.25
    decalin 37.16
    glycerin 235.31
    diglyme 315.97
    acrylic acid 145.5
    isopropyl myristate 89.98
    n-butyric acid 150.02
    acetyl acetate 139.16
    di(2-ethylhexyl) phthalate 80.68
    ethyl propionate 144.11
    nitromethane 425.7
    1,2-diethoxyethane 159.36
    benzonitrile 120.05
    trioctyl phosphate 73.55
    1-bromopropane 186.24
    gamma-valerolactone 344.02
    n-decanol 90.63
    triethyl phosphate 93.44
    4-methyl-2-pentanol 103.64
    propionitrile 163.22
    vinylene carbonate 157.75
    1,1,2-trichlorotrifluoroethane 308.87
    DMS 126.25
    cumene 66.59
    2-octanol 89.96
    2-hexanone 139.44
    octyl acetate 105.11
    limonene 104.46
    1,2-dimethoxyethane 424.44
    ethyl orthosilicate 92.84
    tributyl phosphate 74.47
    diacetone alcohol 247.24
    N,N-dimethylaniline 189.31
    acrylonitrile 204.97
    aniline 149.63
    1,3-propanediol 213.95
    bromobenzene 110.15
    dibromomethane 274.18
    1,1,2,2-tetrachloroethane 324.88
    2-methyl-cyclohexyl acetate 106.17
    tetrabutyl urea 124.99
    diisobutyl methanol 81.6
    2-phenylethanol 121.36
    styrene 87.25
    dioctyl adipate 109.21
    dimethyl sulfate 375.07
    ethyl butyrate 115.27
    methyl lactate 201.07
    butyl lactate 101.06
    diethyl carbonate 90.76
    propanediol butyl ether 149.73
    triethyl orthoformate 103.12
    p-tert-butyltoluene 83.74
    methyl 4-tert-butylbenzoate 178.76
    morpholine 358.16
    tert-butylamine 198.59
    n-dodecanol 80.13
    dimethoxymethane 618.11
    ethylene carbonate 131.9
    cyrene 192.13
    2-ethoxyethyl acetate 134.33
    2-ethylhexyl acetate 88.8
    1,2,4-trichlorobenzene 148.5
    4-methylpyridine 222.61
    dibutyl ether 111.26
    2,6-dimethyl-4-heptanol 81.6
    DEF 374.1
    dimethyl isosorbide 255.01
    tetrachloroethylene 244.95
    eugenol 176.38
    triacetin 144.52
    span 80 143.3
    1,4-butanediol 106.34
    1,1-dichloroethane 234.13
    2-methyl-1-pentanol 95.68
    methyl formate 303.72
    2-methyl-1-butanol 122.21
    n-decane 44.78
    butyronitrile 148.08
    3,7-dimethyl-1-octanol 97.83
    1-chlorooctane 93.21
    1-chlorotetradecane 54.89
    n-nonane 44.25
    undecane 36.98
    tert-butylcyclohexane 36.27
    cyclooctane 45.41
    cyclopentanol 196.11
    tetrahydropyran 238.32
    tert-amyl methyl ether 225.83
    2,5,8-trioxanonane 268.85
    1-hexene 98.48
    2-isopropoxyethanol 184.83
    2,2,2-trifluoroethanol 162.18
    methyl butyrate 160.06

    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