Osmium

22.59 g/cu cm

22.59 @25 °C

Blue-white metal

Hard white metal

5012 °C

5012 °C @760 [mm Hg]

3033 °C

Osmium has the highest specific gravity and melting point of the platinum group metals; metallurgically unworkable

Ionic radius, 69 pm; crystal structure, hexagonal close packed; lattice constant, 273.41 pm; thermal expansion, 6.10X10+6 °C-1; magnetic susceptibility, 5.2X10-8 cu cm/g; Young's modulus, 5.56X10+8 kN/sq m; Poisson's ratio, 0.28; Vicker's hardness, 300-670; temperature coefficient of resistance 4.2X10-3 K-1; electrical resistivity at 0 °C, 8.12 microohm-cm; thermal conductivity, 88 W/m K

Valence 0 to 8, more usual, +3, +4, +6, +8; lustrous, bluish white, extremely hard and brittle even at high temperatures, the solid metal is not affected by air at room temperature, but the powdered or spongy metal slowly gives off osmium tetroxide following oxidation in air

Seven naturally occurring isotopes: (184)Os, 0.02%; (186)Os, 1.6%; (187)Os, 1.6%; (188)Os, 13.3%; (189)Os, 16.1%; (190)Os, 26.4%; (192)Os, 41.0%; artificial radioactive isotopes: 181-183; 185;191;193-195; specific heat at 0 °C, 0.0309 cal/g °C; Mohs' hardness, 7.0

Stable in air in the cold; when finely divided, is slowly oxidized by air even at ordinary temperatures to form tetroxide; attacked by fluorine above 100 °C; by dry chlorine on heating; not attacked by bromine or iodine; attacked by aqua regia, by oxidizing acids over a long period of time; barely affected by HCl, H2SO4; burns in vapor of phosphorus to form phosphide; in vapor of sulfur to form sulfide; attacked by molten alkali hydrosulfates, by potassium hydroxide and oxidizing agents; finely divided osmium absorbs a considerable amount of hydrogen

For more Other Experimental Properties (Complete) data for OSMIUM, ELEMENTAL (6 total), please visit the HSDB record page.

Danger

H228 (97.4%): Flammable solid [Danger Flammable solids]；H315 (96.7%): Causes skin irritation [Warning Skin corrosion/irritation]；H318 (96.1%): Causes serious eye damage [Danger Serious eye damage/eye irritation]；H335 (96.7%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]；H413 (69.1%): May cause long lasting harmful effects to aquatic life [Hazardous to the aquatic environment, long-term hazard]

P210, P240, P241, P261, P264, P264+P265, P271, P273, P280, P302+P352, P304+P340, P305+P354+P338, P317, P319, P321, P332+P317, P362+P364, P370+P378, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 152 reports by companies from 8 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.；Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

Chemical: Osmium

Osmium, powder: HSNO Approval: HSR006788 Approved with controls

A skin irritant; Highly toxic; [Hawley] Powder is strong eye irritant; Effects in high-dose animal studies include convulsions; [MSDSonline] The metals in this group [platinum, palladium, iridium, osmium, rhodium, and ruthenium] generally are nontoxic in the metallic state, but the soluble halide salts (particularly of Pt) and osmium tetroxide are highly reactive. Exposure to these elements results in hypersensitivity allergic reactions in susceptible individuals. [Sullivan, p. 911] See Osmium tetroxide.

Ignites when heated to 100 °C with fluorine. Incandescent reaction in phosphorous vapor.

Violent reaction or ignition with chlorine trichloride or oxygen difluoride.

Metallic osmium is inert, but when heated in air or in a finely divided form it oxidizes to osmium tetroxide.

Chlorine trifluoride is a hypergolic oxidizer with recognized fuels, and contact with the materials following at ambient or slightly elevated temperatures is violent, ignition often occurring. ...Osmium... .

For more Hazardous Reactivities and Incompatibilities (Complete) data for OSMIUM, ELEMENTAL (7 total), please visit the HSDB record page.

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 quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.

...Workers dealing with metallic osmium should be protected from the hazards of osmium tetroxide vapor by adequate ventilation. /Osmium Tetraoxide/

0.28 [mg/m3]

3.1 [mg/m3]

19 [mg/m3]

Osmium belongs to the platinum group metals (ruthenium, osmium, rhodium, iridium, palladium and platinum), which are often found together in nature(1). In the lithosphere, the estimated concentration of platinum group metals range from 0.05 to 0.5 ppm(2). Osmium's elemental abundance is 0.001 ppm(1). During the formation of the earth, the six platinum group metals were most likely concentrated within the earth's iron-nickel core(4). Platinum group metals can be transferred from the earth's interior to the lithosphere by tectonic movements of the earth's crust followed by the eruption of magma(2). Osmium is found in the alloy osmiridium and in all platinum ores(3).

/OTHER TOXICITY INFORMATION/ Osmium metal itself... /is/ probably not harmful to the human organism. Already at relatively low temperatures, however, both osmium and its alloys are oxidized to volatile osmium tetroxide, which is toxic and strongly irritating.

Occupational exposure to osmium compounds may occur through inhalation of dust, and by dermal contact at workplaces where platinum group metals are mined or processed, or where osmium compounds are produced or used. Available monitoring data are limited; however, since osmium has a low abundance in the environment and limited uses, exposure to the general population to osmium compounds is expected to be low. (SRC)

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/

Chemical: Osmium

Osmium, powder: HSNO Approval: HSR006788 Approved with controls

Little is known about the absorption, excretion, and retention of osmium, but it has been suggested that, like many other trace elements, it is an essential nutrient in animal metabolism possible in connection with the oxidation-reduction processes of the organism.

Occurs in the mineral osmiridium and in platinum ores; [Merck Index] Used as a catalyst for steroid synthesis, ammonia formation, and hydrogenation of organic compounds; as a fixing and staining agent for electron microscopy; as hardener for iridium and platinum; for instrument pivots; as alloy with iridium for pen points, fine machine bearings, engraving tools, phonograph needles, and watch bearings; as alloy with tungsten in filaments for high intensity incandescent lamps; [HSDB]

Metal Preparation and Pouring [Category: Foundry]；Metal Machining [Category: Heat or Machine]；Metal Extraction and Refining [Category: Industry]

The major uses of osmium are as a catalyst for steroid synthesis and ammonia formation and as a fixing and staining agent for electron microscopy.

As alloy with iridium for pen points and fine machine bearings; ...as catalyst in hydrogenation of organic compounds.

Hardener for iridium and platinum, instrument pivots, catalyst.

Osmiridium (osmium-iridium alloy) is extremely hard and is employed for pen nibs, engraving tools, phonograph needles and watch bearings.

Osmium: ACTIVE

Osmium easily forms alloys with other platinum group metals and with iron, cobalt, and nickel.