Osmium tetroxide: Difference between revisions

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 451133444

| ImageFileL1 = Osmium-tetroxide-2D-dimensions.svg

| ImageSizeL1 = 130px

| ImageFile2 = Osmium tetroxide.jpg

| ImageSize2 = 270px

|Section1={{Chembox Identifiers

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = P40W033BGM

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 88215

|Section2={{Chembox Properties

| MolarMass = 254.23{{nbsp}}g/mol

| Appearance = White volatile solid

| Odor = Acrid, chlorine-like

| Density = 4.9{{nbsp}}g/cm³<ref>{{ cite web | url = http://www.inchem.org/documents/icsc/icsc/eics0528.htm | publisher = InChem | title = Osmium tetroxide ICSC: 0528 }}</ref>

| MeltingPtC = 40.25

| BoilingPtC = 129.7<ref>{{cite journal |last1=Koda |first1=Yoshio |date=1986 |title=Boiling Points and Ideal Solutions of Ruthenium and Osmium Tetraoxides |url= |journal=Journal of the Chemical Society, Chemical Communications |volume=1986 |issue=17 |pages=1347–1348 |doi=10.1039/C39860001347 |access-date=}}</ref>

| Solubility = 5.70{{nbsp}}g/100{{nbsp}}mL (10&nbsp;°C) <br />6.23{{nbsp}}g/100{{nbsp}}mL (25&nbsp;°C)

| Solvent1 = carbon tetrachloride{{!}}CCl₄

| Solubility1 = 375{{nbsp}}g/100{{nbsp}}mL

| SolubleOther = Soluble in most organic solvents, [[ammonium hydroxide]], [[phosphorus oxychloride]]

| pKa =

| VaporPressure = 7{{nbsp}}mmHg (20&nbsp;°C)<ref name=PGCH/>

|Section3={{Chembox Structure

| Structure_ref = <ref name=s1>{{ cite journal |author1=Krebs, B. |author2=Hasse, K. D. | title = Refinements of the Crystal Structures of KTcO₄, KReO₄ and OsO₄. The Bond Lengths in Tetrahedral Oxo-Anions and Oxides of d⁰ Transition Metals | journal = Acta Crystallographica B | year = 1976 | volume = 32 | issue = 5 | pages = 1334–1337 | doi = 10.1107/S056774087600530X }}</ref>

| SpaceGroup = C2/c

| LattConst_a = 9.379&nbsp;[[Angstrom|Å]]

| LattConst_b = 4.515&nbsp;[[Angstrom|Å]]

| LattConst_c = 8.630&nbsp;[[Angstrom|Å]]

| LattConst_beta = 116.58

| UnitCellVolume = 326.8&nbsp;ų

| UnitCellFormulas = 4

| MolShape = tetrahedral

|Section7={{Chembox Hazards

| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0528.htm ICSC 0528]

| GHSPictograms = {{GHS05}}{{GHS06}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|300|310|314|330}}

| PPhrases = {{P-phrases|260|262|264|270|271|280|284|301+310|301+330+331|302+350|303+361+353|304+340|305+351+338|310|320|321|322|330|361|363|403+233|405|501}}

| NFPA-H = 3

| NFPA-S = OX

| IDLH = 1 mg/m³<ref name=PGCH>{{PGCH|0473}}</ref>

| REL = TWA 0.002{{nbsp}}mg/m³ (0.0002{{nbsp}}ppm) ST 0.006{{nbsp}}mg/m³ (0.0006{{nbsp}}ppm)<ref name=PGCH/>

| PEL = TWA 0.002{{nbsp}}mg/m³<ref name=PGCH/>

| LCLo = 1316{{nbsp}}mg/m³ (rabbit, 30{{nbsp}}min)<br/>423{{nbsp}}mg/m³ (rat, 4{{nbsp}}hr)<br/>423{{nbsp}}mg/m³ (mouse, 4{{nbsp}}hr)<ref>{{IDLH|20816120|Osmium tetroxide (as Os)}}</ref>

|Section8={{Chembox Related

| OtherCations = [[Ruthenium tetroxide]]<br />[[Hassium tetroxide]]

| OtherFunction = [[Osmium(IV) oxide]]

| OtherFunction_label = [[osmium]] [[oxide]]s

| OtherCompounds =

'''Osmium tetroxide''' (also '''osmium(VIII) oxide''') is the [[chemical compound]] with the [[Chemical formula|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 [[Volatility (chemistry)|volatile]]. The compound is colourless, but most samples appear yellow.<ref>{{cite journal | last1 = Girolami | first1 = Gregory | year = 2012 | title = Osmium weighs | journal = Nature Chemistry | volume = 4 | issue = 11| page = 954 | doi = 10.1038/nchem.1479 | pmid = 23089872 | bibcode = 2012NatCh...4..954G | doi-access = free }}</ref> This is most likely due to the presence of the impurity [[Osmium dioxide|OsO₂]], which is yellow-brown in colour.<ref>Cotton and Wilkinson, Advanced Inorganic Chemistry, p.1002</ref> In biology, its property of binding to lipids has made it a widely-used stain in electron microscopy.

Osmium(VIII) oxide forms [[monoclinic]] crystals.<ref name=s1/><ref name=niosh/> It has a characteristic acrid [[chlorine]]-like odor. The [[chemical element|element]] name osmium is derived from ''osme'', [[Greek language|Greek]] for ''odor''. OsO₄ is volatile: it [[sublimation (chemistry)|sublimes]] at [[room temperature]]. It is soluble in a wide range of organic solvents. It is moderately soluble in water, with which it reacts reversibly to form osmic acid (see below).<ref name=thompson>{{ cite web | author = Thompson, M. | publisher = [[Bristol University]] | title = Osmium tetroxide (OsO₄) | url = http://www.chm.bris.ac.uk/motm/oso4/oso4h.htm | access-date = 2012-04-07 }}</ref> ''Pure'' osmium(VIII) oxide is probably colourless;<ref>{{ cite book |author1=Butler, I. S. |author2=Harrod, J. F. | title = Inorganic Chemistry: Principles and Applications | year = 1989 | publisher = Benjamin / Cummings | isbn = 978-0-8053-0247-9 | page = 343 | url = https://books.google.com/books?id=Nd3vAAAAMAAJ | access-date= 2012-04-07 }}</ref> it has been suggested that its yellow hue is attributable due to [[osmium dioxide]] (OsO₂) impurities.<ref>{{ cite book | author = Cotton, F. A. | title = Advanced Inorganic Chemistry | edition = 6th | url = https://books.google.com/books?id=U3MWRONWAmMC | year = 2007 | publisher = J. Wiley | location = New Delhi, India | isbn = 978-81-265-1338-3 | page = 1002 }}</ref> The osmium tetroxide molecule is tetrahedral and therefore nonpolar. This nonpolarity helps OsO₄ penetrate charged cell membranes.

The [[osmium]] of OsO₄ has an [[oxidation number]] of VIII; however, the metal does not possess a corresponding 8+ charge as the bonding in the compound is largely [[covalent]] in character (the [[ionization energy]] required to produce a formal 8+ charge also far exceeds the energies available in normal chemical reactions). The osmium atom exhibits double bonds to the four [[oxide]] [[ligands]], resulting in a [[16-Electron Complexes#16e complexes|16 electron complex]]. This is isoelectronic with [[permanganate]] and [[Chromate ion|chromate]] ions.

OsO₄ is formed slowly when osmium powder reacts with O₂ at ambient temperature. Reaction of bulk solid requires heating to 400&nbsp;°C.<ref name = h&s>{{Housecroft2nd|pages=671–673, 710}}</ref>

:<chem>Os + 2O2 ->[\Delta T] OsO4</chem>

===Oxidation of alkenes===

Alkenes add to OsO₄ to give [[alkoxide|diolate]] species that hydrolyze to ''cis''-diols. The net process is called dihydroxylation. This proceeds via a [3 + 2] [[cycloaddition]] reaction between the OsO₄ and alkene to form an intermediate osmate ester that rapidly hydrolyses to yield the [[Diol#Vicinal diols|vicinal diol]]. As the oxygen atoms are added in a concerted step, the resulting stereochemistry is ''[[Cis-trans isomerism|cis]]''.

:[[File:Dihydroxylation with OsO4.png|thumb|center|600px|Idealized depiction of the cis-dihydroxylation of alkenes.]]

OsO₄ is expensive and highly toxic, making it an unappealing reagent to use in [[stoichiometric]] amounts. However, its reactions are made [[Catalysis|catalytic]] by adding [[reoxidant]]s to reoxidise the Os(VI) by-product back to Os(VIII). Typical reagents include [[hydrogen peroxide|H₂O₂]] ([[Milas hydroxylation]]), [[N-Methylmorpholine N-oxide|N-methylmorpholine N-oxide]] ([[Upjohn dihydroxylation]]) and [[potassium ferricyanide|K₃Fe(CN)₆]]/water. These reoxidants do not react with the alkenes on their own. Other osmium compounds can be used as catalysts, including osmate(VI) salts ([OsO₂(OH)₄)]²⁻, and osmium trichloride hydrate (OsCl₃·''x''H₂O). These species oxidise to osmium(VIII) in the presence of such oxidants.<ref>{{ cite journal | title = On the timing of hydrolysis / reoxidation in the osmium-catalyzed asymmetric dihydroxylation of olefins using potassium ferricyanide as the reoxidant |author1=Ogino, Y. |author2=Chen, H. |author3=Kwong, H.-L. |author4=Sharpless, K. B. | journal = [[Tetrahedron Letters]] | year = 1991 | volume = 32 | issue = 32 | pages = 3965–3968 | doi = 10.1016/0040-4039(91)80601-2 }}</ref>

Lewis bases such as tertiary [[amine]]s and [[pyridine]]s increase the rate of dihydroxylation. This "ligand-acceleration" arises via the formation of [[adduct]] OsO₄L, which adds more rapidly to the alkene. If the amine is chiral, then the dihydroxylation can proceed with enantioselectivity (see [[Sharpless asymmetric dihydroxylation]]).<ref name=catalysis>{{ cite journal |author1=Berrisford, D. J. |author2=Bolm, C. |author3=Sharpless, K. B. | title = Ligand-Accelerated Catalysis | year = 1995 | journal = [[Angewandte Chemie International Edition]] | volume = 34 | issue = 10 | pages = 1059–1070 | doi = 10.1002/anie.199510591 }}</ref> OsO₄ does not react with most carbohydrates.<ref name=stain/>

The process can be extended to give two [[aldehyde]]s in the [[Lemieux–Johnson oxidation]], which uses [[periodate]] to achieve [[diol cleavage]] and to regenerate the catalytic loading of OsO₄. This process is equivalent to that of [[ozonolysis]].

:[[File:Lemieux–Johnson oxidation.svg|600px]]

===Coordination chemistry===

[[File:CSD CIF KEWMEE.png|thumb|144px|left|Structure of OsO₃(N-t-Bu) (multiple bonds are not drawn explicitly), illustrating the type of osmium(VIII)-oxo-imide that adds alkenes en route to the amino alcohol.<ref>{{cite journal|title=Reactions of Dimesityldioxo-Osmium(VI) with Donor Ligands; Reactions of MO₂(2,4,6-Me₃C₆H₂)₂, M = Os or Re, with Nitrogen Oxides. X-Ray Crystal Structures of [2,4,6-Me₃C₆H₂N₂]⁺[OsO₂(ONO₂)₂(2,4,6-Me₃C₆H₂)]^–, OsO(NBu^t)(2,4,6-Me₃C₆H₂)₂, OsO₃(NBu^t), and ReO₃[N(2,4,6-Me₃C₆H₂)₂]|author=Brian S. McGilligan |author2=John Arnold |author3=Geoffrey Wilkinson |author4=Bilquis Hussain-Bates |author5=Michael B. Hursthouse |journal=J. Chem. Soc., Dalton Trans.|year=1990|issue=8|pages=2465–2475 |doi=10.1039/DT9900002465}}</ref>]]OsO₄ is a [[Lewis acid]] and a mild oxidant. It reacts with alkaline [[aqueous solution]] to give the perosmate anion {{chem|OsO|4|(OH)|2|2−}}.<ref>{{Greenwood&Earnshaw2nd}}</ref> This species is easily reduced to [[potassium osmate|osmate]] anion, {{chem|OsO|2|(OH)|4|2-}}.

When the [[Lewis base]] is an [[amine]], adducts are also formed. Thus OsO₄ can be stored in the form of '''osmeth''', in which OsO₄ is [[complexation|complexed]] with [[hexamine]]. Osmeth can be dissolved in [[tetrahydrofuran]] (THF) and diluted in an aqueous [[buffer solution]] to make a dilute (0.25%) working [[Solution (chemistry)|solution]] of OsO₄.<ref>{{ cite web | author = Kiernan, J. A. | publisher = Department of Anatomy & Cell Biology, The University of Western Ontario | url = http://www.histosearch.com/histonet/Nov00A/Re.quotDisposalquotofOsmi.html | title = Re: "Disposal" of Osmium Tetroxide "Waste" }}</ref>

With [[tert-Butylamine|tert-BuNH₂]], the [[imido]] derivative is produced:

:OsO₄ + Me₃CNH₂ → OsO₃(NCMe₃) + H₂O

Similarly, with [[ammonia|NH₃]] one obtains the [[nitrido complex]]:

The [Os(N)O₃]⁻ anion is isoelectronic and isostructural with OsO₄.

OsO₄ is very soluble in [[tert-butyl alcohol]]. In solution, it is readily reduced by hydrogen to osmium metal. The suspended osmium metal can be used to [[catalysis|catalyze]] [[hydrogenation]] of a wide variety of organic chemicals containing double or triple bonds.

:OsO₄ + 4 H₂ → Os + 4 H₂O

OsO₄ undergoes "reductive carbonylation" with [[carbon monoxide]] in methanol at 400&nbsp;K and 200&nbsp;sbar to produce the triangular cluster [[Triosmium dodecacarbonyl|Os₃(CO)₁₂]]:

:3 OsO₄ + 24 CO → Os₃(CO)₁₂ + 12 CO₂<ref name = "h&s"/>

====Oxofluorides====

Osmium forms several oxofluorides, all of which are very sensitive to moisture.

Purple ''cis''-OsO₂F₄ forms at 77&nbsp;K in an anhydrous [[hydrogen fluoride|HF]] solution:<ref>{{ cite journal |author1=Christe, K. O. |author2=Dixon, D. A. |author3=Mack, H. G. |author4=Oberhammer, H. |author5=Pagelot, A. |author6=Sanders, J. C. P. |author7=Schrobilgen, G. J. | title = Osmium tetrafluoride dioxide, ''cis''-OsO₂F₄ | year = 1993 | journal = [[Journal of the American Chemical Society]] | volume = 115 | issue = 24 | pages = 11279–11284 | doi = 10.1021/ja00077a029 }}</ref>

: OsO₄ + 2 KrF₂ → ''cis''-OsO₂F₄ + 2 Kr + O₂

OsO₄ also reacts with F₂ to form yellow OsO₃F₂:<ref name=chem>{{ cite book | author = Cotton, S. A. | title = Chemistry of Precious Metals | publisher = Chapman and Hall | location = London | year = 1997 | isbn = 0-7514-0413-6 }}</ref>

: 2 OsO₄ + 2 F₂ → 2 OsO₃F₂ + O₂

OsO₄ reacts with one equivalent of [Me₄N]F at 298&nbsp;K and 2 equivalents at 253&nbsp;K:<ref name = h&s/>

: OsO₄ + [Me₄N]F → [Me₄N][OsO₄F]

: OsO₄ + 2 [Me₄N]F → [Me₄N]₂[''cis''-OsO₄F₂]

In organic synthesis OsO₄ is widely used to oxidize [[alkene]]s to the [[Vicinal (chemistry)|vicinal]] diols, adding two [[hydroxyl]] groups at the same side ([[syn addition]]). See reaction and mechanism above. This reaction has been made both catalytic ([[Upjohn dihydroxylation]]) and asymmetric ([[Sharpless asymmetric dihydroxylation]]).

Osmium(VIII) oxide is also used in catalytic amounts in the [[Sharpless oxyamination]] to give [[Vicinal (chemistry)|vicinal]] amino-alcohols.

In combination with [[sodium periodate]], OsO₄ is used for the oxidative cleavage of [[alkene]]s ([[Lemieux-Johnson oxidation]]) when the periodate serves both to cleave the diol formed by dihydroxylation, and to reoxidize the OsO₃ back to OsO₄. The net transformation is identical to that produced by [[ozonolysis]]. Below an example from the total synthesis of Isosteviol.<ref>{{ cite journal |author1=Snider, B. B. |author2=Kiselgof, J. Y. |author3=Foxman, B. M. | title = Total Syntheses of (±)-Isosteviol and (±)-Beyer-15-ene-3βべーた,19-diol by Manganese(III)-Based Oxidative Quadruple Free-Radical Cyclization | year = 1998 | journal = [[Journal of Organic Chemistry]] | volume = 63 | issue = 22 | pages = 7945–7952 | doi = 10.1021/jo981238x }}</ref>

[[File:Isosteviol-OsO4.svg|700px]]

OsO₄ is a widely used [[staining]] agent used in [[transmission electron microscopy]] (TEM) to provide contrast to the image.<ref name="Bozzola">{{ cite book |author1=Bozzola, J. J. |author2=Russell, L. D. | chapter = Specimen Preparation for Transmission Electron Microscopy | title = Electron Microscopy: Principles and Techniques for Biologists | year = 1999 | publisher = Jones and Bartlett | location = Sudbury, MA | pages = 21–31 | isbn = 978-0-7637-0192-5 | chapter-url = https://books.google.com/books?id=RqSMzR-IXk0C&pg=PA21 }}</ref> This staining method may also be known in the literature as the OTO<ref>{{Cite journal|last1=Seligman|first1=Arnold M.|last2=Wasserkrug|first2=Hannah L.|last3=Hanker|first3=Jacob S.|title=A new staining method (OTO) for enhancing contrast of lipid--containing membranes and droplets in osmium tetroxide--fixed tissue with osmiophilic thiocarbohydrazide(TCH)|date=1966-08-01|journal=The Journal of Cell Biology|volume=30|issue=2|pages=424–432|doi=10.1083/jcb.30.2.424|issn=0021-9525|pmc=2106998|pmid=4165523}}</ref><ref>{{Citation |last1=Unger |first1=Ann-Katrin |date=2020 |work=Volume Microscopy : Multiscale Imaging with Photons, Electrons, and Ions |pages=165–178 |editor-last=Wacker |editor-first=Irene |place=New York, NY |publisher=Springer US |language=en |doi=10.1007/978-1-0716-0691-9_9 |isbn=978-1-0716-0691-9 |last2=Neujahr |first2=Ralph |last3=Hawes |first3=Chris |last4=Hummel |first4=Eric |title=Improving Serial Block Face SEM by Focal Charge Compensation |series=Neuromethods |volume=155 |s2cid=226563386 |editor2-last=Hummel |editor2-first=Eric |editor3-last=Burgold |editor3-first=Steffen |editor4-last=Schröder |editor4-first=Rasmus}}</ref> (osmium-thiocarbohydrazide-osmium) method, or osmium impregnation<ref>{{Cite journal|last1=Tapia|first1=Juan C.|last2=Kasthuri|first2=Narayanan|last3=Hayworth|first3=Kenneth|last4=Schalek|first4=Richard|last5=Lichtman|first5=Jeff W.|last6=Smith|first6=Stephen J|last7=Buchanan|first7=JoAnn|date=2012-01-12|title=High contrast en bloc staining of neuronal tissue for field emission scanning electron microscopy|journal=Nature Protocols|volume=7|issue=2|pages=193–206|doi=10.1038/nprot.2011.439|issn=1754-2189|pmc=3701260|pmid=22240582}}</ref> technique or simply as osmium staining. As a [[lipid]] stain, it is also useful in [[scanning electron microscopy]] (SEM) as an alternative to [[sputter coating]]. It embeds a heavy metal directly into cell membranes, creating a high electron scattering rate without the need for coating the membrane with a layer of metal, which can obscure details of the cell membrane. In the staining of the [[plasma membrane]], osmium(VIII) oxide binds [[phospholipid]] head regions, thus creating contrast with the neighbouring [[protoplasm]] (cytoplasm). Additionally, osmium(VIII) oxide is also used for fixing biological samples in conjunction with HgCl₂. Its rapid killing abilities are used to quickly kill live specimens such as protozoa. OsO₄ stabilizes many proteins by transforming them into gels without destroying structural features. Tissue proteins that are stabilized by OsO₄ are not coagulated by alcohols during dehydration.<ref name=stain>{{ cite book | author = Hayat, M. A. | title = Principles and Techniques of Electron Microscopy: Biological Applications | publisher = Cambridge University Press | year = 2000 | pages = 45–61 | isbn = 0-521-63287-0 | url = https://books.google.com/books?id=nfsVMH8it1kC }}</ref> Osmium(VIII) oxide is also used as a stain for lipids in optical microscopy.<ref>{{ cite journal | title = A simple protocol for paraffin-embedded myelin sheath staining with osmium(VIII) oxide for light microscope observation |author1=Di Scipio, F. |author2=Raimondo, S. |author3=Tos, P. |author4=Geuna, S. | journal = Microscopy Research and Technique | year = 2008 | volume = 71 | issue = 7 | pages = 497–502 | doi = 10.1002/jemt.20577 | pmid = 18320578 |s2cid=9404999 }}</ref> OsO₄ also stains the human cornea (see [[Osmium tetroxide#Safety considerations|safety considerations]]).

[[File:Resin-Embedded Transmission Electron Microscope Sample.jpg|thumb|left|A sample of cells fixed/stained with osmium tetroxide (black) embedded in epoxy resin (amber). The cells are black as a result of the effects of osmium tetroxide.]]

OsO₄ is an intermediate in the extraction of osmium from its ores. Osmium-containing residues are treated with sodium peroxide (Na₂O₂) forming Na₂[OsO₄(OH)₂], which is soluble. When exposed to [[chlorine]], this salt gives OsO₄. In the final stages of refining, crude OsO₄ is dissolved in alcoholic [[NaOH]] forming Na₂[OsO₂(OH)₄], which, when treated with [[ammonium chloride|NH₄Cl]], to give (NH₄)₄[OsO₂Cl₂]. This salt is reduced under [[hydrogen]] to give osmium.<ref name=thompson/>

OsO₄ allowed for the confirmation of the soccer ball model of [[buckminsterfullerene]], a 60-atom [[carbon]] [[allotrope]]. The [[adduct]], formed from a derivative of OsO₄, was C₆₀(OsO₄)(4-''tert''-[[butyl]][[pyridine]])₂. The adduct broke the fullerene's symmetry, allowing for crystallization and confirmation of the structure of C₆₀ by [[X-ray crystallography]].<ref>{{ cite journal |author1=Hawkins, J. M. |author2=Meyer, A. |author3=Lewis, T. A. |author4=Loren, S. |author5=Hollander, F. J. | title = Crystal Structure of Osmylated C₆₀: Confirmation of the Soccer Ball Framework | year = 1991 | journal = [[Science (journal)|Science]] | volume = 252 | issue = 5003 | pages = 312–313 | doi = 10.1126/science.252.5003.312 | pmid = 17769278 |bibcode=1991Sci...252..312H |s2cid=36255748 }}</ref>

===Medicine===

The only known clinical use of osmium tetroxide is for the treatment of arthritis.<ref>{{cite journal|last=Sheppeard|first=H.|author2=D. J. Ward|journal=Rheumatology|date=1980|volume=19|pages=25–29|doi=10.1093/rheumatology/19.1.25|pmid=7361025|title=Intra-articular osmic acid in rheumatoid arthritis: five years' experience|issue=1}}</ref> The lack of reports of long-term side effects from the local administration of osmium tetroxide (OsO₄) suggest that osmium itself can be [[biocompatible]], though this depends on the osmium compound administered.

[[File:Label for ampoules of OsO4.jpg|thumb|right|300px|Label with poison warning]]

OsO₄ will irreversibly stain the human [[cornea]], which can lead to blindness. The permissible exposure limit for osmium(VIII) oxide (8 hour time-weighted average) is 2&nbsp;µg/m³.<ref name=niosh>{{ cite web | url = https://www.cdc.gov/niosh/idlh/20816120.html | title = Osmium tetroxide (as Os) | work = Documentation for Immediately Dangerous to Life or Health Concentrations (IDLHs)| date = 2 November 2018 | publisher = Centers for Disease Control }}</ref> Osmium(VIII) oxide can penetrate plastics and food packaging, and therefore must be stored in glass under refrigeration.<ref name=stain/>

{{reflist}}

*[https://www.cdc.gov/niosh/npg/npgd0473.html NIOSH Pocket Guide to Chemical Hazards]

*[https://www.cdc.gov/niosh/topics/osmium-tetroxide/ CDC - Osmium Tetroxide - NIOSH Workplace Safety and Health Topic]

*[https://www.organic-chemistry.org/chemicals/oxidations/osmiumtetroxide.shtm Chemical Reactions]

{{Oxides}}

[[Category:Transition metal oxides]]

[[Category:Foul-smelling chemicals]]