osmium dioxide

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 428742843

| ImageFile = Rutile-unit-cell-3D-balls.png

| ImageName = Osmium(IV) oxide

| IUPACName = Osmium dioxide

| OtherNames = Osmium(IV) oxide

|Section1={{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|??}}

| CASNo = 12036-02-1

| ChemSpiderID = 163069

| PubChem = 187574

| StdInChI=1S/2O.Os

| StdInChIKey = XSXHWVKGUXMUQE-UHFFFAOYSA-N

| SMILES = O=[Os]=O

}}

|Section2={{Chembox Properties

| Formula = OsO2

| MolarMass = 222.229 g/mol

| Appearance = black or yellow brown

| Density = 11.4 g/cm3

| MeltingPtC = 500

| MeltingPt_notes = (decomposes)

| BoilingPt =

| Solubility =

| SolubleOther =

| pKa =

}}

|Section7={{Chembox Hazards

| ExternalSDS =

| GHS_ref =

}}

|Section8={{Chembox Related

| OtherAnions =

| OtherFunction = Osmium tetroxide

| OtherFunction_label = osmium oxides

| OtherCompounds =

| Related_ref = [http://www.webelements.com/compounds/osmium/osmium_dioxide.html OsO2 at webelements]

}}

}}

Osmium dioxide is an inorganic compound with the formula OsO2. It exists as brown to black crystalline powder, but single crystals are golden and exhibit metallic conductivity. The compound crystallizes in the rutile structural motif, i.e. the connectivity is very similar to that in the mineral rutile.

Preparation

OsO2 can be obtained by the reaction of osmium with a variety of oxidizing agents, including, sodium chlorate, osmium tetroxide, and nitric oxide at about 600 °C.{{cite book| page = 1465| title = Inorganic chemistry|author1=A. F. Holleman |author2=E. Wiberg |name-list-style=amp | publisher = Academic Press| year = 2001| isbn = 0-12-352651-5}}{{cite journal|journal = Journal of the Less Common Metals| title = Neutronenbeugungsuntersuchungen am Osmium(IV)-oxid| doi=10.1016/0022-5088(69)90074-5 |author1=Thiele G. |author2=Woditsch P. |year = 1969|volume = 17|issue = 4|pages = 459 }} Using chemical transport, one can obtain large crystals of OsO2, sized up to 7x5x3 mm3. Single crystals show metallic resistivity of ~15 μΩ cm. A typical transport agent is {{chem|O|2}} via the reversible formation of volatile OsO4:{{cite book | last1 = Rogers | first1 = D. B. | last2 = Butler | first2 = S. R. | last3 = Shannon | first3 = R. D. | chapter = Single Crystals of Transition-Metal Dioxides | year = 1972 | title = Inorganic Syntheses | volume = XIII | pages = 135–145 | doi = 10.1002/9780470132449.ch27 | isbn = 9780470132449 }}

: OsO2 + O2 {{eqm}} OsO4

Reactions

OsO2 does not dissolve in water, but is attacked by dilute hydrochloric acid.{{cite journal|title = Metallic nature of osmium dioxide|author1=J. E. Greedan |author2=D. B. Willson |author3=T. E. Haas | journal = Inorg. Chem.| year = 1968 |volume = 7|issue = 11 | pages = 2461–2463| doi = 10.1021/ic50069a059}}{{cite journal| title = Growth and characterization of {{chem|OsO|2}} single crystals| journal = Journal of Crystal Growth| volume = 262| issue = 1–4| year= 2004 | page = 271| doi = 10.1016/j.jcrysgro.2003.10.021| last1 = Yen| first1 = P}} The crystals have rutile structure.{{cite journal|journal = Acta Chemica Scandinavica | year = 1970 |volume = 24 | pages = 123–128|title = Precision Determination of the Crystal Structure of Osmium Dioxide|

author = Boman C.E.|doi = 10.3891/acta.chem.scand.24-0123|last2 = Danielsen|first2 = Jacob|last3 = Haaland|first3 = Arne|author3-link=Arne Haaland|last4 = Jerslev|first4 = Bodil|last5 = Schäffer|first5 = Claus Erik|last6 = Sunde|first6 = Erling|last7 = Sørensen|first7 = Nils Andreas |doi-access = free}} Unlike osmium tetroxide, OsO2 is not toxic.{{cite journal| author = Smith, I.C., B.L. Carson, and T.L. Ferguson| year = 1974| title = Osmium: An appraisal of environmental exposure. | journal = Env Health Perspect | volume= 8| pages = 201–213| pmid = 4470919| pmc = 1474945| doi = 10.2307/3428200| publisher = National Institute of Environmental Health Sciences| jstor = 3428200}}

References

{{reflist}}

{{Osmium compounds}}

{{oxides}}

Category:Osmium compounds

Category:Transition metal oxides