Molybdenum (IV) oxide

Crystal structure
	__ Mo 4+ __ O 2−
Crystal system	monoclinic
Space group	P 2 1 / c
Lattice parameters	a = 558.4 pm, b = 484.2 pm, c = 560.8 pm, β = 120.59 °
General
Surname	Molybdenum (IV) oxide
other names	Molybdenum dioxide
Ratio formula	MoO 2
Brief description	red-brown, odorless solid
External identifiers / databases
EC number	242-637-9
ECHA InfoCard	100,038,746
PubChem	29320
ChemSpider	27268
Wikidata	Q415673
properties
Molar mass	127.94 g mol −1
Physical state	firmly
density	6.47 g cm −3
Melting point	1100 ° C (decomposition)
solubility	poor in water (1.4 g l −1 at 20 ° C)
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 302-332-319-335
	P: 261-280-304 + 340-305 + 351 + 338-405-501
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Molybdenum (IV) oxide is a chemical compound from the group of oxides .

Occurrence

Molybdenum (IV) oxide occurs very rarely naturally as the mineral tugarinovite .

Extraction and presentation

Molybdenum (IV) oxide can be obtained by reducing molybdenum (VI) oxide with hydrogen , ammonia or elemental molybdenum above a temperature of 470 ° C:

{\ displaystyle \ mathrm {2 \ MoO_ {3} + Mo \ rightarrow 3 \ MoO_ {2}}}

Larger single crystals can be obtained by chemical transport of polycrystalline molybdenum (IV) oxide with iodine in a temperature gradient of 900 to 700 ° C.

properties

Molybdenum (IV) oxide is a brown-violet solid that is sparingly soluble in water. It has a monoclinic crystal structure with the space group P 2 ₁ / c (space group no. 14) (a = 558.4 pm, b = 484.2 pm, c = 560.8 pm, β = 120.59 °). Very finely divided powder is self-igniting in air. Template: room group / 14

use

Molybdenum (IV) oxide can be used as a catalyst for the dehydrogenation of alcohols.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f Entry for CAS no. 18868-43-4 in the GESTIS substance database of the IFA , accessed on December 11, 2012 (JavaScript required)
↑ WebElements: molybdenum dioxide
↑ Mineral Atlas: Tugarinovite
↑ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A .; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5
^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 91st – 100th, improved and greatly expanded edition. Walter de Gruyter, Berlin 1985, ISBN 3-11-007511-3 , p. 1100.
↑ ^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. 1542.
↑ AA Balandin and ID Rozhdestvenskaya, Russian Chemical Bulletin, 8, 11, (1959), 1573 doi : 10.1007 / BF00914749

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f Entry for CAS no. 18868-43-4 in the GESTIS substance database of the IFA , accessed on December 11, 2012 (JavaScript required)

[2] WebElements: molybdenum dioxide

[3] Mineral Atlas: Tugarinovite

[4] Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A .; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5

[Holleman-5] AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 91st – 100th, improved and greatly expanded edition. Walter de Gruyter, Berlin 1985, ISBN 3-11-007511-3 , p. 1100.

[brauer-6] 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. 1542.

[7] AA Balandin and ID Rozhdestvenskaya, Russian Chemical Bulletin, 8, 11, (1959), 1573 doi : 10.1007 / BF00914749