Editing Osmium tetroxide (section)

{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 451133444
| ImageFileL1 = Osmium-tetroxide-2D-dimensions.svg
| ImageClassL1 = skin-invert 
| ImageSizeL1 = 130px
| ImageNameL1 = Stick model osmium tetroxide
| ImageFileR1 = Osmium-tetroxide-ED-3D-balls-A.png
| ImageNameR1 = Ball and stick model of osmium tetroxide
| ImageClassR1 = bg-transparent 
| ImageFile2 = Osmium tetroxide.jpg
| ImageSize2 = 270px
| PIN = Osmium tetraoxide
| SystematicName = Tetraoxoosmium
| OtherNames = Osmium(VIII) oxide
|Section1={{Chembox Identifiers
| InChI1 = 1/4O.Os/rO4Os/c1-5(2,3)4
| InChIKey1 = VUVGYHUDAICLFK-TYHKRQCIAE
| CASNo = 20816-12-0
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = P40W033BGM
| PubChem = 30318
| ChemSpiderID = 28158
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChEBI_Ref = {{ebicite|correct|EBI}} 
| ChEBI = 88215
| EINECS = 244-058-7
| UNNumber = UN 2471
| MeSHName = Osmium+tetroxide
| RTECS = RN1140000
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/4O.Os
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = VUVGYHUDAICLFK-UHFFFAOYSA-N
| SMILES = O=[Os](=O)(=O)=O
| InChI = 1S/4O.Os
| InChIKey = VUVGYHUDAICLFK-UHFFFAOYSA-N}}
|Section2={{Chembox Properties
| Formula = OsO<sub>4</sub>
| MolarMass = 254.23{{nbsp}}g/mol
| Appearance = White volatile solid
| Odor = Acrid, chlorine-like
| Density = 4.9{{nbsp}}g/cm<sup>3</sup><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{{!}}CCl<sub>4</sub>
| 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 KTcO<sub>4</sub>, KReO<sub>4</sub> and OsO<sub>4</sub>. The Bond Lengths in Tetrahedral Oxo-Anions and Oxides of d<sup>0</sup> Transition Metals | journal = Acta Crystallographica B | year = 1976 | volume = 32 | issue = 5 | pages = 1334–1337 | doi = 10.1107/S056774087600530X |bibcode=1976AcCrB..32.1334K }}</ref>
| CrystalStruct = Monoclinic, [[Pearson symbol|mS20]]
| 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;Å<sup>3</sup>
| 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-F = 0
| NFPA-R = 1
| NFPA-S = OX
| IDLH = 1 mg/m<sup>3</sup><ref name=PGCH>{{PGCH|0473}}</ref>
| REL = TWA 0.002{{nbsp}}mg/m<sup>3</sup> (0.0002{{nbsp}}ppm) ST 0.006{{nbsp}}mg/m<sup>3</sup> (0.0006{{nbsp}}ppm)<ref name=PGCH/>
| PEL = TWA 0.002{{nbsp}}mg/m<sup>3</sup><ref name=PGCH/>
| LCLo = 1316{{nbsp}}mg/m<sup>3</sup> (rabbit, 30{{nbsp}}min)<br/>423{{nbsp}}mg/m<sup>3</sup> (rat, 4{{nbsp}}hr)<br/>423{{nbsp}}mg/m<sup>3</sup> (mouse, 4{{nbsp}}hr)<ref>{{IDLH|20816120|Osmium tetroxide (as Os)}}</ref>
 }}
|Section8={{Chembox Related
| OtherAnions =
| 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]] OsO<sub>4</sub>. 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|osmium dioxide (OsO<sub>2</sub>)]], 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.