Osmium (IV) oxide

Crystal structure
	__ Os 4+ __ O 2−
General
Surname	Osmium (IV) oxide
other names	Osmium dioxide
Ratio formula	OsO 2
Brief description	black solid; golden single crystals;
External identifiers / databases
PubChem	187574
ChemSpider	163069
Wikidata	Q2044728
properties
Molar mass	222.20 g mol −1
Physical state	firmly
density	11.4 g cm −3
Melting point	650 ° C (decomposition)
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 302
	P: 264-270-301 + 312-330-501
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Osmium (IV) oxide is an inorganic chemical compound of osmium from the group of oxides .

Extraction and presentation

Osmium (IV) oxide can be obtained by reducing osmium tetroxide in a hydrogen - nitrogen gas stream or by reacting potassium hexachloro- osmate K ₂ OsCl ₆ with sodium carbonate at high temperatures.

Single crystals of the oxide can be produced using a CVT (Chemical Vapor Transport) method . For this purpose, elemental osmium is first converted to the polycrystalline oxide with sodium chlorate in a melted and evacuated ampoule in a 2-stage reaction at initially 300 ° C and then 650 ° C. The ampoule with the oxide is then placed in a 2-zone oven so that half of the ampoule is in one of the zones. While one half of the ampoule is heated to 960 ° C, the other half is kept at 900 ° C. After a reaction time of 2 days (with 0.15 g of elemental osmium initially used), the ampoule is allowed to cool and, after opening, golden single crystals of the target compound about 2 mm in size are obtained.

{\ displaystyle {\ ce {3Os + 2NaClO3 -> 3OsO2 + 2NaCl}}}

{\ displaystyle {\ ce {OsO2 + O2 <=> OsO4 _ {(g)}}}}

properties

Osmium (IV) oxide is purchased as a black solid that is insoluble in water, while the freshly made compound is golden in color in both poly- and monocrystalline forms. In air it slowly changes into osmium tetroxide and can react pyrophorically with atmospheric oxygen. It has a crystal structure of rutile type (a = 451 microns, c = 319 pm). The dihydrate is a deep black powder which, like the anhydrate, tends to form osmium tetroxide in air. It is soluble in hydrochloric acid to form dihydrogen hexachloro-osmate H ₂ [OsCl ₆ ].

Individual evidence

↑ ^a ^b ^c ^d ^e ^f data sheet Osmium (IV) oxide, Os 83% min at AlfaAesar, accessed on September 1, 2013 ( PDF )(JavaScript required) .
↑ ^a ^b ^c D. B. Rogers et al .: Single crystals of transition-metal dioxides - B. Osmium dioxide . In: FA Cotton (Ed.): Inorganic Syntheses . tape 13 . McGraw-Hill Book Company, Inc., 1972, ISBN 07-013208-9 ( defective ) , p. 135-145 (English).
^ Jean d'Ans, Ellen Lax, Roger Blachnik: Pocket book for chemists and physicists . Springer DE, 1998, ISBN 3-642-58842-5 , pp. 646 f . ( limited preview in Google Book search).
↑ ^a ^b Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1745.

[Alfa-1] ↑ ^a ^b ^c ^d ^e ^f data sheet Osmium (IV) oxide, Os 83% min at AlfaAesar, accessed on September 1, 2013 ( PDF )(JavaScript required) .

[IS13-2] D. B. Rogers et al .: Single crystals of transition-metal dioxides - B. Osmium dioxide . In: FA Cotton (Ed.): Inorganic Syntheses . tape 13 . McGraw-Hill Book Company, Inc., 1972, ISBN 07-013208-9 ( defective ) , p. 135-145 (English).

[Jean_d’Ans,_Ellen_Lax,_Roger_Blachnik-3] Jean d'Ans, Ellen Lax, Roger Blachnik: Pocket book for chemists and physicists . Springer DE, 1998, ISBN 3-642-58842-5 , pp. 646 f . ( limited preview in Google Book search).

[brauer-4] Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1745.