Osmium tetroxide

Osmium tetroxide
Stick model osmium tetroxide
Stick model osmium tetroxide
Ball and stick model of osmium tetroxide
Ball and stick model of osmium tetroxide
Names
Preferred IUPAC name
Osmium tetraoxide
Systematic IUPAC name
Tetraoxoosmium
Other names
Osmium(VIII) oxide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.040.038 Edit this at Wikidata
EC Number
  • 244-058-7
MeSH Osmium+tetroxide
RTECS number
  • RN1140000
UNII
UN number UN 2471
  • InChI=1S/4O.Os checkY
    Key: VUVGYHUDAICLFK-UHFFFAOYSA-N checkY
  • 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
OsO4
Molar mass 254.23 g/mol
Appearance White volatile solid
Odor Acrid, chlorine-like
Density 4.9 g/cm3[1]
Melting point 40.25 °C (104.45 °F; 313.40 K)
Boiling point 129.7[2] °C (265.5 °F; 402.8 K)
5.70 g/100 mL (10 °C)
6.23 g/100 mL (25 °C)
Solubility Soluble in most organic solvents, ammonium hydroxide, phosphorus oxychloride
Solubility in CCl4 375 g/100 mL
Vapor pressure 7 mmHg (20 °C)[3]
Structure[4]
Monoclinic, mS20
C2/c
a = 9.379 Å, b = 4.515 Å, c = 8.630 Å
α = 90°, β = 116.58°, γ = 90°
326.8 Å3
4
tetrahedral
Hazards
GHS labelling:
GHS05: CorrosiveGHS06: Toxic
Danger
H300, H310, H314, H330
P260, P262, P264, P270, P271, P280, P284, P301+P310, P301+P330+P331, P302+P350, P303+P361+P353, P304+P340, P305+P351+P338, P310, P320, P321, P322, P330, P361, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
3
0
1
OX
Lethal dose or concentration (LD, LC):
1316 mg/m3 (rabbit, 30 min)
423 mg/m3 (rat, 4 hr)
423 mg/m3 (mouse, 4 hr)[5]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 0.002 mg/m3[3]
REL (Recommended)
 TWA 0.002 mg/m3 (0.0002 ppm) ST 0.006 mg/m3 (0.0006 ppm)[3]
IDLH (Immediate danger)
 1 mg/m3[3]
Safety data sheet (SDS) ICSC 0528
Related compounds
Other cations
 Ruthenium tetroxide
Hassium tetroxide
Related osmium oxides
 Osmium(IV) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

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.[6] This is most likely due to the presence of the impurity OsO2, which is yellow-brown in colour.[7] In biology, its property of binding to lipids has made it a widely-used stain in electron microscopy.

  1. ^ "Osmium tetroxide ICSC: 0528". InChem.
  2. ^ Koda, Yoshio (1986). "Boiling Points and Ideal Solutions of Ruthenium and Osmium Tetraoxides". Journal of the Chemical Society, Chemical Communications. 1986 (17): 1347–1348. doi:10.1039/C39860001347.
  3. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0473". National Institute for Occupational Safety and Health (NIOSH).
  4. ^ Krebs, B.; Hasse, K. D. (1976). "Refinements of the Crystal Structures of KTcO4, KReO4 and OsO4. The Bond Lengths in Tetrahedral Oxo-Anions and Oxides of d0 Transition Metals". Acta Crystallographica B. 32 (5): 1334–1337. Bibcode:1976AcCrB..32.1334K. doi:10.1107/S056774087600530X.
  5. ^ "Osmium tetroxide (as Os)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  6. ^ Girolami, Gregory (2012). "Osmium weighs". Nature Chemistry. 4 (11): 954. Bibcode:2012NatCh...4..954G. doi:10.1038/nchem.1479. PMID 23089872.
  7. ^ Cotton and Wilkinson, Advanced Inorganic Chemistry, p.1002