HuagongsheHuagongshe Chemistry Print Report · For research reference only
Osmium Tetroxide
OsO4 · OSMIUM(VIII) OXIDE · OSMIUM TETRAOXIDE · Osmium oxide · OSMIC ACID · OSMIUM(VIII)-TETROXIDE · tetraoxoosmium · os encat
Identifiers & Physical Properties
| CAS No. | 20816-12-0 |
|---|---|
| Molecular formula | O4Os |
| Average molar mass | 254.2 g/mol |
| Monoisotopic mass | 255.94113918 g/mol |
| SMILES | [O]=[Os](=[O])(=[O])=[O] |
| InChIKey | VUVGYHUDAICLFK-UHFFFAOYSA-N |
| PubChem CID | 30318 |
| ChEBI | CHEBI:88215 |
| EC No. | 244-058-7 |
| DTXSID | DTXSID5042245 |
Chemical & Physical Properties
| Topological polar surface area | 68.3 |
|---|---|
| Hydrogen bond donors | 0 |
| Hydrogen bond acceptors | 4 |
| Rotatable bonds | 0 |
| Heavy atoms | 5 |
| Formal charge | 0 |
| Complexity | 138 |
| Chemical classes | Metals -> Metals, Inorganic Compounds |
| Odor | Acrid, chlorine-like odorUnpleasant odor.Acrid, chlorine-like odor detectable at 2 ppm (20 mg/m3) |
| Density | 5.1 (NIOSH, 2024) - Denser than waterwill sink5.10 (Calculated)Relative density (water = 1): 4.95.1 @25 °C1.04 |
| Color/Form | Pale yellow solidmonoclinic crystalsDimorphic compd with both crystalline and amorphous formsColorless, crystalline solid, or pale-yellow mass [Note: A liquid above 105 degrees F]. |
| Solubility | 6 % at 77 °F (NIOSH, 2024)Sol in benzene, alcohol, ether, ammonium hydroxide, and phosphorus oxychloridesolubility in carbon tetrachloride @ 25 deg: 375 g/100 gSolubility (g/100 cc solvent): 5.70 g in water @ 10 °C6.23 g in water @ 25 °C250 +/- 10 g in carbon tetrachloride @ 20 °CIn water, 7.24 (g/100 g) at 25 °CSolubility in water, g/100ml at 25 °C: 6(77 °F): 6%Soluble in alcohol, ether, chloroform, benzene, ammonium hydroxide, phosphorus oxychloride and carbon tetrachlorideSoluble in chloroform, alcohol and ethers.Soluble in water, organic solvents, benzene, alcohol, ether, ammonium hydroxide, phosphorus oxychloride and carbon tetrachloride. |
| Boiling point | 266 °F at 760 mmHg (NIOSH, 2024)130.0 °C at 760 mm Hgbegins to sublime and distill well below bp130 °C131.2 °C @760 [mm Hg] |
| Decomposition | When heated to decomposition, it emits toxic fumes of /osmium/. |
| Melting point | 105 °F (NIOSH, 2024)40.6 °C42 °C40°C |
| Vapor density | Relative vapor density (air = 1): 8.88.8 (vs air) |
| Odor threshold | Odor Threshold Low: 0.0019 [mg/m3]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). |
| Vapor pressure | 7 mmHg (NIOSH, 2024)7.0 [mmHg]11 mm Hg at 27 °CVapor pressure, kPa at 27 °C: 1.511 [mm Hg] @27 °C7 mmHg at 20 °C |
| Ionization Potential | 12.60 eV |
| Bulk density | 1500kg/m3 |
| Flash point | -40 °C |
| Storage conditions | 2-8°C |
| Physical state | Solution |
| Color | White to yellow,or lemon yellow |
| Specific gravity | 5.10 |
| pH | 6 (20°C, 25g/L in H2O) |
| Specific heat capacity | Cp(gas): 0.29 J/(g·K), at 25℃ |
| Sensitivity | Air Sensitive |
| Merck | 14,6893 |
| crystal system | Monoclinic |
| Space group | C2/c |
| Lattice constant | a/nm |
| GHS pictogram | GHS05,GHS06 |
| Signal word | Danger |
| GHS hazard statements | H300+H310+H330-H314 |
| GHS precautionary statements | P260-P270-P280-P303+P361+P353-P304+P340+P310-P305+P351+P338 |
| Hazard symbols | O,T,C,T+,F,Xi,Xn |
| Risk statements (R) | 8-23/24/25-40-34-26/27/28-42/43-11-67-66-36/37/38-19-36/38-36/37 |
| Safety statements (S) | 17-26-27-36/37/39-45-7/9-36/37-16-28-23 |
| UN transport number | UN 2471 |
| Occupational exposure band (OEB) | E |
| Occupational exposure limit (OEL) | TWA: 0.002 mg/m3 (0.0002 ppm), STEL: 0.006 mg/m3 (0.0006 ppm) |
| Water hazard class (WGK) | 3 |
| RTECS number | RN1140000 |
| TSCA inventory status | TSCA listed |
| Hazard class | 6.1Acute Tox. 1 DermalAcute Tox. 2 InhalationAcute Tox. 2 OralEye Dam. 1Skin Corr. 1B |
| Packing group | I |
| Customs code | 28439090 |
| Storage class | 6.1A - Combustible acute toxic Cat. 1 and 2very toxic hazardous materials |
| Hazardous substances data | 20816-12-0(Hazardous Substances Data) |
| Toxicity | LD50 oral (rat) 14 mg/kg LCLO inhal (rat) 40 ppm (4 h) PEL (OSHA) 0.0002 ppm (0.002 mg/m3) TLV-TWA (ACGIH) 0.0002 ppm (0.002 mg/m3) STEL (ACGIH) 0.0006 ppm (0.006 mg/m3) |
| Immediately dangerous to life or health concentration | 1 mg Os/m3 |
| Excepted quantities | Max Inner Pack (1g or 1ml) and Max Outer Pack (300g or 300ml) |
Safety & Regulations
| GHS classification | DangerH300: Fatal if swallowed [Danger Acute toxicity, oral]P260, P262, P264, P270, P271, P280, P284, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P320, P321, P330, P361+P364, P363, P403+P233, P405, and P501 (click each P-code to see the statement)H300 (100%): Fatal if swallowed [Danger Acute toxicity, oral]P233, P260, P262, P264, P270, P271, P280, P284, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P320, P321, P330, P342+P316, P361+P364, P363, P403, P403+P233, P405, and P501 (click each P-code to see the statement) |
|---|---|
| Regulatory information | Chemical: Osmium oxide (OsO4), (T-4)-Osmium (VIII) oxide: HSNO Approval: HSR002793 Approved with controlsThe New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.) |
| Other safety information | IMAP assessments - Osmium oxide (OsO4), (T-4)-: Environment tier I assessment |
| DOT label | Poison |
| Fire hazards | Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:· Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.Not combustible but enhances combustion of other substances. Risk of fire and explosion on contact with combustible substances. |
| Fire potential | Not combustible.Not combustible but enhances combustion of other substances. |
| Health hazards | Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:· TOXIC and/or CORROSIVEinhalation, ingestion or skin contact with material may cause severe injury or death. |
| Hazards summary | A skin and respiratory irritant, OsO4 can cause pulmonary edema in animals exposed to high concentrations. [ACGIH] A lachrymator[ChemFinder] Tear drawing and corrosive to the skin, eyes, and respiratory tractMay cause kidney injury after prolonged or repeated exposure[ICSC] Osmium tetroxide can cause chronic bronchitis. [LaDou, p. 382] May cause severe burns[CAMEO] Based on animal studies, osmium tetroxide bioaccumulates after chronic exposure and may cause kidney and liver damage. [HSDB] See Osmium. |
| DOT ID and guide | 2471 154 |
| Reactive group | Oxidizing Agents, Strong |
| EC classification | Symbol: T+R: 26/27/28-34S: (1/2)-7/9-26-45 |
| UN classification | UN Hazard Class: 6.1UN Pack Group: I |
| RCRA requirements | P087As stipulated in 40 CFR 261.33, when osmium tetroxide, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to federal and/or state hazardous waste regulations. Also defined as a hazardous waste is any container or inner liner used to hold this waste or any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5(e)). |
| Fire fighting | Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:In case of fire in the surroundings, use appropriate extinguishing media. |
| First aid measures | Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.First rinse with plenty of water for at least 15 minutes, then remove contaminated clothes and rinse again. Refer for medical attention .First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.Rinse mouth. Give nothing to drink. Rest. Refer for medical attention . |
| Accidental release measures | · CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. |
| First aid | Excerpt from NIOSH Pocket Guide for Osmium tetroxide:General First Aid:(General first aid procedures) |
| Safe storage | Separated from combustible substances, reducing agents and food and feedstuffs. Ventilation along the floor. |
| Exposure control and personal protection | · Wear positive pressure self-contained breathing apparatus (SCBA).TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016]. |
| Fire fighting procedures | If material on fire or involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Solid streams of water may spread the fire.In case of fire in the surroundings: all extinguishing agents allowed. |
| Storage conditions | Separated from combustible and reducing substances, food and feedstuffs. Ventilation along the floor.Because of its high acute toxicity, osmium tetroxide should be handled in the laboratory using the "basic prudent practices" of Chapter 5.C, supplemented by the additional precautions for work with compounds of high toxicity (Chapter 5.D). In particular, all work with osmium tetroxide should be conducted in a fume hood to prevent exposure by inhalation, and splash goggles and impermeable gloves should be worn at all times to prevent eye and skin contact. Osmium tetroxide as solid or solutions should be stored in tightly sealed containers, and these should be placed in secondary containers. |
| Cleanup methods | Ventilate area of spill or leak. Collect material liquid containing osmium tetroxide should be absorbed in vermiculite, dry sand, earth, or a similar material.Sweep spilled substance into containersif appropriate, moisten first to prevent dusting then remove to safe place. Do NOT absorb in saw-dust or other combustible absorbents.Environmental considerations: Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Cover solids with a plastic sheet to prevent dissolving gin rain or fire fighting water.Environmental considerations: Water spill: Use natural barriers or oil spill control booms to limit spill travel. Remove trapped material with suction hoses.For more Cleanup Methods (Complete) data for OSMIUM TETROXIDE (6 total), please visit the HSDB record page. |
| Nonfire spill response | Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]: |
| Disposal methods | Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number P087, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.[Cautiously make a 5% solution of the material in water or dilute acid. There may be a vigorous, exothermic reaction and fumes may be generated due to hydrolysis of the material. Control any reaction by cooling and by the rate of addition. Gradually add dilute ammonium hydroxide to pH 10. Filter off any precipitate for disposal in a chemical landfill. If no precipitation occurs, gradually adjust the pH from 10 to 6, stopping when precipitation occurs.Excess osmium tetroxide solutions can be rendered safer by reaction with sodium sulfite to produce insoluble osmium dioxide. Ethanol will also react to produce the dioxide. Corn oil or sodium sulfide may also be used to deactivate osmium tetroxide. Osmium-containing waste should be placed in a tightly sealed, labeled container and handled according to your institution's waste disposal guidelines. For more information on disposal procedures, see Chapter 7 of this volume.SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air qualitypotential migration in soil or watereffects on animal, aquatic, and plant lifeand conformance with environmental and public health regulations. |
| Spillage disposal | Evacuate danger area! Consult an expert! Personal protection: complete protective clothing including self-contained breathing apparatus. Ventilation. Do NOT let this chemical enter the environment. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Then store and dispose of according to local regulations. Do NOT absorb in saw-dust or other combustible absorbents. |
| Target organs | Eyes, skin, respiratory system |
| Ecotoxicity values | LC50 Nitocra spinipes ((Harpacticoidea Crustacea) 10-50 ug/L/96 hrstaticEC50 Tubifex tubifex (Tubificid wormintoxication, immobilization) 14 ug/L/24 hr (95% confidence interval: 9-21 ug/L)static /Technical product/intoxication, immobilization) 9 ug/L/48 hr (95% confidence interval: 7-12.1 ug/L)renewal /Technical product/intoxication, immobilization) 6.7 ug/L/96 hr (95% confidence interval: 5.1-7.2 ug/L) |
| Environmental fate | ATMOSPHERIC FATE: Osmium tetroxide is a volatile osmium compound(1). It would not be expected to persist in the environment(SRC), since osmium tetroxide is readily reduced by organic matter(1). |
| Adverse effects | Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation. |
| Exposure routes | The substance can be absorbed into the body by inhalation of its aerosol or vapour and by ingestion.inhalation, ingestion, skin and/or eye contact |
| Toxicity summary | The acute toxicity of osmium tetroxide is high, and it is a severe irritant of the eyes and respiratory tract. Exposure to osmium tetroxide vapor can damage the cornea of the eye. Irritation is generally the initial symptom of exposure to low concentrations of osmium tetroxide vapor, and lacrimation, a gritty feeling in the eyes, and the appearance of rings around lights may also be noted. In most cases, recovery occurs in a few days. Concentrations of vapor that do not cause immediate irritation can have an insidious cumulative effectsymptoms may not be noted until several hours after exposure. Contact of the eyes with concentrated solutions of this substance can cause severe damage and possible blindness. Inhalation can cause headache, coughing, dizziness, lung damage, and difficult breathing and may be fatal. Contact of the vapor with skin can cause dermatitis, and direct contact with the solid can lead to severe irritation and burns. Exposure to osmium tetroxide via inhalation, skin contact, or ingestion can lead to systemic toxic effects involving liver and kidney damage. Osmium tetroxide is regarded as a substance with poor warning properties. Chronic exposure to osmium tetroxide can result in an accumulation of osmium compounds in the liver and kidney and damage to these organs. Osmium tetroxide has been reported to cause reproductive toxicity in animalsthis substance has not been shown to be carcinogenic or to show reproductive or developmental toxicity in humans. |
| Signs and Symptoms | Burning sensation. Cough. Headache. Wheezing. Shortness of breath. Visual disturbances. Symptoms may be delayed.Redness. Skin burns. Pain. Skin discoloration. Blisters.Redness. Pain. Blurred vision. Loss of vision. Severe deep burns.Abdominal cramps. Burning sensation. Shock or collapse. See Inhalation.irritation eyes, respiratory systemlacrimation (discharge of tears), visual disturbanceconjunctivitiscough, dyspnea (breathing difficulty)dermatitis |
| Effluent Concentrations | UNCLAIMED OSMIUM TETROXIDE FROM COPPER SMELTERS THAT REACHES WASTEWATER STREAMS IS PROBABLY RAPIDLY REDUCED BY ORGANIC MATTER TO NONTOXIC OSMIUM DIOXIDE OR OS METAL, WHICH WOULD SETTLE OUT IN THE SEDIMENT OF WATERCOURSE. |
| ICSC Environmental Data | This substance may be hazardous to the environment. Special attention should be given to crustacea. |
| Medical Surveillance | Initial medical screening: Employees should be screened for history of certain medical conditions which might place employee at increased risk from osmium tetroxide exposure: Eye disease: osmium tetroxide is an eye irritant and in workers has caused symptoms and signs of keratitis epithelia with corneal edema. Persons with pre-existing eye disorders may be more susceptible to the effects of diseasePulmonary disease: In persons with impaired pulmonary function, especially those with obstructive airway diseases, the breathing /of osmium tetroxide may result in/ exacerbation of symptoms due to its irritant properties Kidney disease: osmium tetroxide causes mild kidney damage in animals. Persons with pre-existing kidney disease may be more susceptible to the effects of this agentSkin disease: osmium tetroxide is a primary skin irritant. Persons with pre-existing skin disorders may be more susceptible to the effects of this agent. |
| Human Toxicity Excerpts | /HUMAN EXPOSURE STUDIES/ /A 1946 report described/ concentrations of osmium tetroxide ranging from 0.1 to 0.6 mg/cu m /were found/ in the air of a precious metal refining plant. The workers suffered from lacrimation and vison disturbances such as gritty feeling in the eyes and the appearance of rings around lights. Some employees complained of headache, conjunctivitis and cough./SIGNS AND SYMPTOMS/ Osmium tetroxide vapors ... /in low concentration caused/ bronchitis, bronchial spasms and difficulty in breathing ... Longer exposure can result in damage to cornea, blindness... inflammatory disorders of lungs and kidneys. Upon contact it discolors the skin green or black and causes dermatitis and ulceration./SIGNS AND SYMPTOMS/ With sufficient concentration.../eye/ irritation with lacrimation and sensation of foreign body is induced... This may be accompanied by irritation of nose and throat. Respiratory irritation...and with repeated exposure asthma may develop./SIGNS AND SYMPTOMS/ Concentrations of vapor which do not cause immediate sensation of irritation have insidious cumulative action with latent period... Symptoms and signs are... keratitis epithelialis with corneal epithelial edema. Victim sees halos or colored rings around lights, suffers blurring of vision and painful scratchy sensation in eyes.For more Human Toxicity Excerpts (Complete) data for OSMIUM TETROXIDE (11 total), please visit the HSDB record page. |
| Artificial Pollution Sources | UNCLAIMED OSMIUM TETROXIDE FROM COPPER SMELTERS ... REACHES WASTEWATER STREAMSOsmium tetroxide is the most industrially important osmium compound(1)its use as an oxidation catalyst(1) may result in the release of osmium compounds through various waste streams(SRC). |
| CERCLA reportable quantities | Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 1000 lb or 454 kg. The toll free number of the NRC is (800) 424-8802In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b). |
| Occupational exposure band (OEB) | E |
| Occupational exposure limit (OEL) | TWA: 0.002 mg/m3 (0.0002 ppm), STEL: 0.006 mg/m3 (0.0006 ppm) |
| Water hazard class (WGK) | 3 |
| Immediately dangerous to life or health concentration | 1 mg Os/m3 |
| TSCA inventory status | TSCA listed |
| RTECS number | RN1140000 |
| UN transport number | UN 2471 |
| Customs code | 28439090 |
| Toxicity | LD50 oral (rat) 14 mg/kg LCLO inhal (rat) 40 ppm (4 h) PEL (OSHA) 0.0002 ppm (0.002 mg/m3) TLV-TWA (ACGIH) 0.0002 ppm (0.002 mg/m3) STEL (ACGIH) 0.0006 ppm (0.006 mg/m3) |
| Risk statements (R) | 8-23/24/25-40-34-26/27/28-42/43-11-67-66-36/37/38-19-36/38-36/37 |
| Signal word | Danger |
| GHS pictogram | GHS05,GHS06 |
| Hazard symbols | O,T,C,T+,F,Xi,Xn |
| Safety statements (S) | 17-26-27-36/37/39-45-7/9-36/37-16-28-23 |
| Hazard class | 6.1Acute Tox. 1 DermalAcute Tox. 2 InhalationAcute Tox. 2 OralEye Dam. 1Skin Corr. 1B |
| Storage class | 6.1A - Combustible acute toxic Cat. 1 and 2very toxic hazardous materials |
| Packing group | I |
| GHS hazard statements | H300+H310+H330-H314 |
| Excepted quantities | Max Inner Pack (1g or 1ml) and Max Outer Pack (300g or 300ml) |
| GHS precautionary statements | P260-P270-P280-P303+P361+P353-P304+P340+P310-P305+P351+P338 |
| Hazardous substances data | 20816-12-0(Hazardous Substances Data) |
Applications & Uses
Uses
Osmium tetroxide is used in histopathological laboratories to stain the adipose tissue and as a stabilizing agent in scanning electron microscopy. In the chemical industry, it is used as a catalyst in the organic synthesis, particularly as the oxidizing agent in olefin-to-glycol conversion (546, 567). In the past, osmium tetroxide in the form of aqueous solution was used in forensic medicine to examine fingerprints. Osmium tetroxide is also used in medicine to treat rheumatoid arthritis.
Uses
Oxidizing agent, particularly for converting olefins to glycols. Catalyzes chlorate, peroxide, periodate, and other oxidations: P. N. Rylander, Organic Syntheses with Noble Metal Catalysts (Academic Press, New York, 1973) pp 121-144. As fixing and staining agent for cell and tissue studies.
Uses
Osmium (VIII) tetraoxide (Os8+ + 4O2-→ OsO4) is a yellow crystal and probably the most important compound used as an oxidizing agent, as a biological stain in microscopy, and to detect fingerprints.
General Description
A colorless or yellow solid with a pungent odor of chlorine. Melting point about 104°F. Boiling point 266°F (begins to sublime below melting point). Density 4.9 g / cm3. Soluble in alcohol. Toxic by inhalation and a strong irritant to the eyes and mucous membranes.
Preparation & Synthesis
Preparation
Osmium tetroxide is obtained as an intermediate during recovery of osmium metal from osmiridium or other noble metal minerals (See Osmium). In general, oxidation of an aqueous solution of an osmium salt or complex, such as sodium osmate with nitric acid, yields the volatile tetroxide which may be distilled out from the solution. In the laboratory, the compound can be prepared by oxidation of the osmium tetrachloride, OsCl4, or other halide solutions with sodium hypochlorite followed by distillation. Osmium tetroxide may also be produced by heating finely divided osmium metal in a stream of oxygen or air at 300 to 400°C.