Molybddntrioxid Chemische Eigenschaften,Einsatz,Produktion Methoden
Beschreibung
Molmasse 143.95 g/mol. Wei?es Pulver, das sich beim Erhitzen gelb f?rbt und nach dem Erkalten wieder farblos wird. Beim Sublimieren erh?lt man gl?nzende, farblose, kristalline Flitter. F. 795 ℃, Kp. 1155 ℃. L?slichkeit in Wasser bei 28 ℃: 0.490 g MoO3; Kristallstruktur orthorhombisch (a = 3.92, b = 13.94, c = 3.66 A).
R-S?tze Betriebsanweisung:
R36/37:Reizt die Augen und die Atmungsorgane.
R48/20/22:Gesundheitssch?dlich: Gefahr ernster Gesundheitssch?den bei l?ngerer Exposition durch Einatmen und durch Verschlucken.
S-S?tze Betriebsanweisung:
S22:Staub nicht einatmen.
S23:Gas/Rauch/Dampf/Aerosol nicht einatmen(geeignete Bezeichnung(en) vom Hersteller anzugeben).
S25:Berührung mit den Augen vermeiden.
Chemische Eigenschaften
Molybdenum trioxide is an odorless, white crystalline powder that turns yellow when heated.
Molybdenum trioxide is perhaps the most important compound of molybdenum. Pure molybdenum trioxide is used in chemical and catalyst manufacture. The technical product is added to steel as an alloying agent. Molybdenum trioxide also serves as a catalyst in the petroleum industry and as a component of ceramics, enamels and pigments.
Physikalische Eigenschaften
Soft white powder; orthorhombic crystals; turns yellow on heating; density 4.69 g/cm
3 at 21°C; melts at 795°C without decomposition to a dark yellow liquid; vapor pressure 20 torr at 851°C and 200 torr at 1,014°C; boils at 1,155°C; sparingly soluble in cold water (1.066 g/L at 18°C) and moderately soluble in hot water (20.55 g/L at 70°C); dissolves in acids and alkalies.
Verwenden
Molybdenum trioxide (MnO3) is a compound used to make enamels adhere to metals.
synthetische
Molybdenum(VI) oxide is obtained by igniting molybdenum or its compounds in air:
2Mo + 3O2 → 2MoO3
2MoS2 + 7O2 → 2MoO3 + 4SO2
MoS2 + 4O2 → MoO3 + SO2 + SO3
Roasting the sulfide is carried out in a multiple-hearth roaster under controlled temperature and airflow. The product mixture is sublimed to obtain high purity oxide.
Purified molybdenum(VI) oxide also is made by prolonged heating of ammonium molybdate in air:
(NH4)2Mo2O7 → 2MoO3 + 2NH3 + H2O
An alternative method involves repeatedly evaporating a mixture of ammonium molybdate and nitric acid. Ammonium nitrate so formed is separated from the product molybdenum(VI) oxide by extraction with water:
(NH4)2Mo2O7 + 2HNO3 → 2MoO3 + 2NH4NO3 + H2O
Allgemeine Beschreibung
Colorless to white or yellow odorless solid. Sinks in water.
Air & Water Reaktionen
Insoluble in water.
Reaktivit?t anzeigen
Molybdenum trioxide reacts violently with chlorine trifluoride, lithium, potassium and sodium. Readily combines with acids and bases to form a series of polymeric compounds. Incompatible with interhalogens and metals. A violent detonation occurs when heated with molten magnesium.
Hazard
Toxic material.
Health Hazard
Compound is relatively nontoxic. Dust irritates eyes.
Brandgefahr
Flash point data for Molybdenum trioxide are not available, but Molybdenum trioxide is probably non-flammable.
Sicherheitsprofil
Poison by ingestion,
subcutaneous, and intraperitoneal routes.
Human systemic effects by inhalation:
pulmonary fibrosis and cough. Questionable
carcinogen with experimental neoplastigenic
data. A powerful irritant. Explodes on
contact with molten magnesium. Violent reaction with interhalogens (e.g., bromine
pentafluoride, chlorine trifluoride).
Incandescent reaction with hot sodium,
potassium, or lithium. When heated to
decomposition it emits toxic fumes of Mo.
m?gliche Exposition
Molybdenum trioxide is used in
agriculture; manufacture of metallic molybdenum, ceramic
glazes; enamels, pigments, and in analytical chemistry.
Versand/Shipping
UN2811 Toxic solids, organic, n.o.s., Hazard
Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name
Required.
l?uterung methode
Crystallise it from water (1g/50mL) between 70o and 0o. The solubility in H2O is 0.1% at 18o, and 2% at 70o. It is a white powder which turns yellow reversibly on heating. It sublimes readily at 1155o/760mm. [Hein & Herzog Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II p 1412 1965.]
Inkompatibilit?ten
Explodes on contact with molten
magnesium. Violent reaction with strong oxidizers, such as
chlorine trifluoride; bromine pentafluoride. Not compatible
with strong acids; active metals (sodium, potassium,
lithium).
Molybddntrioxid Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
