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Topic summary

Osmium tetroxide

Osmium tetroxide
Names Preferred IUPAC name
Osmium tetraoxide
Systematic IUPAC name
Tetraoxoosmium
Other names
Osmium(VIII) oxide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard100.040.038EC Number
  • 244-058-7
MeSHOsmium+tetroxide
RTECS number
  • RN1140000
UNII
UN numberUN 2471
  • InChI=1S/4O.Os
    Key: VUVGYHUDAICLFK-UHFFFAOYSA-N
  • InChI=1S/4O.Os
    Key: VUVGYHUDAICLFK-UHFFFAOYSA-N
  • InChI=1/4O.Os/rO4Os/c1-5(2,3)4
    Key: VUVGYHUDAICLFK-TYHKRQCIAE
  • O=[Os](=O)(=O)=O
Properties OsO4Molar mass254.23g/mol Appearance White volatile solid OdorAcrid, chlorine-like Density4.9g/cm Melting point40.25 °C (104.45 °F; 313.40 K) Boiling point129.7 °C (265.5 °F; 402.8 K) 5.70g/100mL (10 °C)
6.23g/100mL (25 °C) SolubilitySoluble in most organic solvents, ammonium hydroxide, phosphorus oxychlorideSolubility in CCl4375g/100mL Vapor pressure7mmHg (20 °C) Structure Monoclinic, mS20C2/c
a = 9.379 Å, b = 4.515 Å, c = 8.630 Å
α = 90°, β = 116.58°, γ = 90°
326.8 Å 4 tetrahedral Hazards GHS labelling: DangerH300, H310, H314, H330P260, P262, P264, P270, P271, P280, P284, P301+P310, P301+P330+P331, P302+P350, P303+P361+P353, P304+P340, P305+P351+P338, P310, P320, P321, P330, P361, P363, P403+P233, P405, P501NFPA 704 (fire diamond)
3
0
1
OX
Lethal dose or concentration (LD, LC): 1316mg/m (rabbit, 30min)
423mg/m (rat, 4hr)
423mg/m (mouse, 4hr) NIOSH (US health exposure limits):
PEL (Permissible)
TWA 0.002mg/m
REL (Recommended)
TWA 0.002mg/m (0.0002ppm) ST 0.006mg/m (0.0006ppm)
IDLH (Immediate danger)
1 mg/m Safety data sheet (SDS) ICSC 0528Related compounds
Other cations
Ruthenium tetroxide
Hassium tetroxide
Related osmiumoxides
Osmium(IV) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Osmium tetroxide (also osmium(VIII) oxide) is the chemical compound with the formula OsO4. The compound is noteworthy for its many uses, despite its toxicity and the rarity of osmium. It also has a number of unusual properties, one being that the solid is volatile. The compound is colourless, but most samples appear yellow. This is most likely due to the presence of the impurity osmium dioxide (OsO2), which is yellow-brown in colour. In biology, its property of binding to lipids has made it a widely used stain in electron microscopy.

Wikipedia source