Molybdenum trioxide Chemical Properties

Melting point:

795 °C(lit.)

Boiling point:

1155 °C

Density 

4.692

vapor pressure 

0Pa at 20℃

Flash point:

1155°C subl.

storage temp. 

Store at +5°C to +30°C.

solubility 

0.49g/l

form 

Sublimed Powder

Specific Gravity

4.69

color 

White to gray

Water Solubility 

0.5 g/L (20 ºC)

Merck 

14,6239

Exposure limits

ACGIH: TWA 10 mg/m3; TWA 3 mg/m3
NIOSH: IDLH 5000 mg/m3

InChIKey

JKQOBWVOAYFWKG-UHFFFAOYSA-N

CAS DataBase Reference

1313-27-5(CAS DataBase Reference)

NIST Chemistry Reference

Molybdenum(vi) oxide(1313-27-5)

IARC

2B (Vol. 118) 2018

EPA Substance Registry System

Molybdenum trioxide (1313-27-5)

Safety Information

Hazard Codes 

Xn,Xi

Risk Statements 

36/37-48/20/22-40

Safety Statements 

22-23-25-36/37

WGK Germany 

1

RTECS 

QA4725000

TSCA 

Yes

HazardClass 

6.1

HS Code 

28257000

Hazardous Substances Data

1313-27-5(Hazardous Substances Data)

Toxicity

LD50 orally in Rabbit: 2689 mg/kg LD50 dermal Rat > 2000 mg/kg

MSDS

• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS
• Language:English Provider:ALFA

Molybdenum trioxide Usage And Synthesis

Chemical Properties

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.

Physical properties

Soft white powder; orthorhombic crystals; turns yellow on heating; density 4.69 g/cm³ 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.

Uses

Molybdenum(VI) oxide is used in catalyst compositions to carry out desulfurization of petroleum feedstocks and to remove nitrogen-containing compounds from petroleum fractions. Other uses of this oxide include preparation of various molybdate salts and as reagents for chemical analyses.

Uses

Chiefly as a reagent for chemical analysis.Used for trace metal analysis.

Uses

Molybdenum trioxide (MnO3) is a compound used to make enamels adhere to metals.

Preparation

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

General Description

Colorless to white or yellow odorless solid. Sinks in water.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

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.

Fire Hazard

Flash point data for Molybdenum trioxide are not available, but Molybdenum trioxide is probably non-flammable.

Flammability and Explosibility

Nonflammable

Safety Profile

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.

Potential Exposure

Molybdenum trioxide is used in agriculture; manufacture of metallic molybdenum, ceramic glazes; enamels, pigments, and in analytical chemistry.

Shipping

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Purification Methods

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.]

Incompatibilities

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).

Molybdenum trioxide(1313-27-5)Related Product Information

• Ferric oxide
• Magnesium oxide
• Chromium(III) oxide
• Ammonium metavanadate
• AMMONIUM 6-MOLYBDONICKELATE II
• Trioxide
• Molybdenum
• Chromium(VI) oxide
• VANADIUM (III) OXIDE
• Iron oxide
• NITRIC OXIDE
• Boron oxide
• Sulfur trioxide
• Bismuth trioxide
• Zinc oxide
• Arsenic(III) oxide
• ETHYLENE OXIDE
• Diantimony trioxide