Osmium dioxide

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Osmium dioxide
Rutile-unit-cell-3D-balls.png
Names
IUPAC name
Osmium dioxide
Other names
Osmium(IV) oxide
Identifiers
PubChem CID
Properties
OsO2
Molar mass 222.229 g/mol
Appearanceblack or yellow brown
Density 11.4 g/cm3
Melting point 500 °C (932 °F; 773 K)(decomposes)
Related compounds [1]
Related osmium oxides
Osmium tetroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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.

Contents

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. [2] [3] 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 O
2
via the reversible formation of volatile OsO4: [4]

OsO2 + O2 OsO4

Reactions

OsO2 does not dissolve in water, but is attacked by dilute hydrochloric acid. [5] [6] The crystals have rutile structure. [7] Unlike osmium tetroxide, OsO2 is not toxic. [8]

Related Research Articles

Osmium Chemical element, symbol Os and atomic number 76

Osmium is a chemical element with the symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element. When experimentally measured using x-ray crystallography, it has a density of 22.59 g/cm3. Manufacturers use its alloys with platinum, iridium, and other platinum-group metals to make fountain pen nib tipping, electrical contacts, and in other applications that require extreme durability and hardness.

Oxide Chemical compound with at least one oxygen atom

An oxide is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. Metal oxides thus typically contain an anion of oxygen in the oxidation state of −2. Most of the Earth's crust consists of solid oxides, the result of elements being oxidized by the oxygen in air or in water. Even materials considered pure elements often develop an oxide coating. For example, aluminium foil develops a thin skin of Al2O3 (called a passivation layer) that protects the foil from further corrosion. Certain elements can form multiple oxides, differing in the amounts of the element combining with the oxygen. Examples are carbon, iron, nitrogen (see nitrogen oxide), silicon, titanium, lithium, and aluminium. In such cases the oxides are distinguished by specifying the numbers of atoms involved, as in carbon monoxide and carbon dioxide, or by specifying the element's oxidation number, as in iron(II) oxide and iron(III) oxide.

Osmium tetroxide Chemical compound

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 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.

Noble metal Metallic elements that are nearly chemically inert

In chemistry, noble metals are metallic elements that show outstanding resistance to chemical attack even at high temperatures. They are well known for their catalytic properties and associated capacity to facilitate or control the rates of chemical reactions. The short list of chemically noble metals comprises ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt), gold (Au) and silver (Ag). In periodic table terms, an analogy can be made between the noble metals and the noble gases, which are mainly unreactive.

Dinitrogen tetroxide Chemical compound

Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russia rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium mixture with nitrogen dioxide. Its molar mass is 92.011 g/mol.

Manganese dioxide Chemical compound

Manganese dioxide is the inorganic compound with the formula MnO
2
. This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for MnO
2
is for dry-cell batteries, such as the alkaline battery and the zinc–carbon battery. MnO
2
is also used as a pigment and as a precursor to other manganese compounds, such as KMnO
4
. It is used as a reagent in organic synthesis, for example, for the oxidation of allylic alcohols. MnO
2
is α polymorph that can incorporate a variety of atoms in the "tunnels" or "channels" between the manganese oxide octahedra. There is considerable interest in α-MnO
2
as a possible cathode for lithium-ion batteries.

Periodate Ion

Periodate is an anion composed of iodine and oxygen. It is one of a number of oxyanions of iodine and is the highest in the series, with iodine existing in oxidation state +7. Unlike other perhalogenates, such as perchlorate, it can exist in two forms: metaperiodateIO
4
and orthoperiodateIO5−
6
. In this regard it is comparable to the tellurate ion from the adjacent group. It can combine with a number of counter ions to form periodates, which may also be regarded as the salts of periodic acid.

Dihydroxylation is the process by which an alkene is converted into a vicinal diol. Although there are many routes to accomplish this oxidation, the most common and direct processes use a high-oxidation-state transition metal. The metal is often used as a catalyst, with some other stoichiometric oxidant present. In addition, other transition metals and non-transition metal methods have been developed and used to catalyze the reaction.

Ruthenium tetroxide is the inorganic compound with the formula RuO4. It is a yellow volatile solid that melts near room temperature. It has the odour of ozone. Samples are typically black due to impurities. The analogous OsO4 is more widely used and better known. One of the few solvents in which RuO4 forms stable solutions is CCl4.

Ruthenium(IV) oxide Chemical compound

Ruthenium(IV) oxide is the inorganic compound with the formula RuO2. This black solid is the most common oxide of ruthenium. It is widely used as an electrocatalyst for producing chlorine, chlorine oxides, and O2 catalyst is ruthenium(IV) oxide. Like many dioxides, RuO2 adopts the rutile structure.

Tungsten(IV) oxide Chemical compound

Tungsten(IV) oxide is the chemical compound with the formula WO2. The bronze-colored solid crystallizes in a monoclinic cell. The rutile-like structure features distorted octahedral WO6 centers with alternate short W–W bonds (248 pm). Each tungsten center has the d2 configuration, which gives the material a high electrical conductivity.

Rhodium(II) acetate Chemical compound

Rhodium(II) acetate is the coordination compound with the formula Rh2(AcO)4, where AcO is the acetate ion (CH
3
CO
2
). This dark green powder is slightly soluble in polar solvents, including water. It is used as a catalyst for cyclopropanation of alkenes. It is a widely studied example of a transition metal carboxylate complex.

Molybdenum dioxide is the chemical compound with the formula MoO2. It is a violet-colored solid and is a metallic conductor. The mineralogical form of this compound is called tugarinovite, and is only very rarely found.

The Lemieux–Johnson or Malaprade–Lemieux–Johnson oxidation is a chemical reaction in which an olefin undergoes oxidative cleavage to form two aldehyde or ketone units. The reaction is named after its inventors, Raymond Urgel Lemieux and William Summer Johnson, who published it in 1956. The reaction proceeds in a two step manner, beginning with dihydroxylation of the alkene by osmium tetroxide, followed by a Malaprade reaction to cleave the diol using periodate. Excess periodate is used to regenerate the osmium tetroxide, allowing it to be used in catalytic amounts. The Lemieux–Johnson reaction ceases at the aldehyde stage of oxidation and therefore produces the same results as ozonolysis.

Rhenium(IV) oxide Chemical compound

Rhenium(IV) oxide or rhenium dioxide is the inorganic compound with the formula ReO2. This gray to black crystalline solid is a laboratory reagent that can be used as a catalyst. It adopts the rutile structure.

Niobium dioxide Chemical compound

Niobium dioxide, is the chemical compound with the formula NbO2. It is a bluish-black non-stoichiometric solid with a composition range of NbO1.94-NbO2.09. It can be prepared by reducing Nb2O5 with H2 at 800–1350 °C. An alternative method is reaction of Nb2O5 with Nb powder at 1100 °C.

Osmium(IV) chloride Chemical compound

Osmium(IV) chloride or osmium tetrachloride is the inorganic compound composed of osmium and chlorine with the empirical formula OsCl4. It exists in two polymorphs (crystalline forms). The compound is used to prepare other osmium complexes.

A sulfite sulfate is a chemical compound that contains both sulfite and sulfate anions [SO3]2− [SO4]2−. These compounds were discovered in the 1980s as calcium and rare earth element salts. Minerals in this class were later discovered. Minerals may have sulfite as an essential component, or have it substituted for another anion as in alloriite. The related ions [O3SOSO2]2− and [(O2SO)2SO2]2− may be produced in a reaction between sulfur dioxide and sulfate and exist in the solid form as tetramethyl ammonium salts. They have a significant partial pressure of sulfur dioxide.

Osmium iodide refers to compounds of osmium with the formula OsIn. Several have been mentioned in the literature, but all iodides except tetraiodide has been verified by X-ray crystallography.

Transition metal nitrate complex Compound of nitrate ligands

A transition metal nitrate complex is a coordination compound containing one or more nitrate ligands. Such complexes are common starting reagents for the preparation of other compounds.

References

  1. OsO2 at webelements
  2. A. F. Holleman & E. Wiberg (2001). Inorganic chemistry. Academic Press. p. 1465. ISBN   0-12-352651-5.
  3. Thiele G.; Woditsch P. (1969). "Neutronenbeugungsuntersuchungen am Osmium(IV)-oxid". Journal of the Less Common Metals. 17 (4): 459. doi:10.1016/0022-5088(69)90074-5.
  4. Rogers, D. B.; Butler, S. R.; Shannon, R. D. (1972). "Single Crystals of Transition-Metal Dioxides". Inorganic Syntheses. XIII: 135–145. doi:10.1002/9780470132449.ch27. ISBN   9780470132449.
  5. J. E. Greedan; D. B. Willson; T. E. Haas (1968). "Metallic nature of osmium dioxide". Inorg. Chem. 7 (11): 2461–2463. doi:10.1021/ic50069a059.
  6. Yen, P (2004). "Growth and characterization of OsO
    2
    single crystals". Journal of Crystal Growth. 262 (1–4): 271. doi:10.1016/j.jcrysgro.2003.10.021.
  7. Boman C.E.; Danielsen, Jacob; Haaland, Arne; Jerslev, Bodil; Schäffer, Claus Erik; Sunde, Erling; Sørensen, Nils Andreas (1970). "Precision Determination of the Crystal Structure of Osmium Dioxide". Acta Chemica Scandinavica. 24: 123–128. doi: 10.3891/acta.chem.scand.24-0123 .
  8. Smith, I.C., B.L. Carson, and T.L. Ferguson (1974). "Osmium: An appraisal of environmental exposure". Env Health Perspect. National Institute of Environmental Health Sciences. 8: 201–213. doi:10.2307/3428200. JSTOR   3428200. PMC   1474945 . PMID   4470919.CS1 maint: multiple names: authors list (link)