
- IUPAC name
- trioxomolybdenum
- Molecular formula
- MoO3
- Molecular weight
- 143.95 g/mol
- Exact mass
- 145.890147 Da
- Topological polar surface area
- 51.2 Ų
- Hydrogen-bond donors
- 0
- Hydrogen-bond acceptors
- 3
- Covalent units
- 1
- Defined stereocentres
- 0
Also known as
16 more reported names
External database identifiers
- ChEBI:CHEBI:30627
- EPA DTXSID:DTXSID7020899
- PubMed:33038468
- PubMed:30389395
- PubMed:9029048
Evidence from additional scientific databases
NIH PubChem PUG-View
Attributed physical-property, hazard, environmental and use annotations.
- Boiling Point: 2111 °F at 760 mmHg (Sublimes) (NTP, 1992) Source: CAMEO Chemicals
- Boiling Point: 1155 °C, SUBLIMES Source: Hazardous Substances Data Bank (HSDB)
- Boiling Point: 1155 °C @760 [mm Hg] Source: PAC Chemical Database, U.S. Department of Energy
- Color/Form: WHITE OR SLIGHTLY YELLOW TO SLIGHTLY BLUISH POWDER OR GRANULES Source: Hazardous Substances Data Bank (HSDB)
- Color/Form: COLORLESS OR WHITE YELLOW RHOMBIC CRYSTALS Source: Hazardous Substances Data Bank (HSDB)
- Color/Form: WHITE POWDER AT ROOM TEMP, YELLOW AT ELEVATED TEMP Source: Hazardous Substances Data Bank (HSDB)
- Density: 4.69 at 68 °F (USCG, 1999) - Denser than water; will sink Source: CAMEO Chemicals
- Density: 4.69 @ 26 °C/4 °C Source: Hazardous Substances Data Bank (HSDB)
- Density: 4.696 @25 °C Source: PAC Chemical Database, U.S. Department of Energy
- Melting Point: 1463 °F (NTP, 1992) Source: CAMEO Chemicals
- Melting Point: 795 °C Source: Hazardous Substances Data Bank (HSDB)
- Melting Point: 802 °C Source: PAC Chemical Database, U.S. Department of Energy
- Odor: None Source: Hazardous Substances Data Bank (HSDB)
- Physical Description: Molybdenum trioxide appears as colorless to white or yellow odorless solid. Sinks in water. (USCG, 1999) Source: CAMEO Chemicals
- Physical Description: Large Crystals; CBI; Dry Powder; Other Solid; Wet Solid; Liquid; Dry Powder; Other Solid; Dry Powder; Large Crystals Source: EPA Chemical Data Reporting (CDR)
- Physical Description: White or slightly yellow to slightly bluish solid; [Merck Index] Light green odorless powder; Partially soluble in water (1.07 g/L at 18 deg C); [MSDSonline] A soluble compound; [ACGIH] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
- Solubility: less than 1 mg/mL at 75 °F (NTP, 1992) Source: CAMEO Chemicals
- Solubility: After strong ignition it is very slightly sol in acids Source: Hazardous Substances Data Bank (HSDB)
- Solubility: 0.490 g/1000 cc water @ 28 °C Source: Hazardous Substances Data Bank (HSDB)
- Solubility: Sol in concentrated mineral acids Source: Hazardous Substances Data Bank (HSDB)
- Solubility: Sol in soln of alkali hydroxides and soln of potassium bitartrate Source: Hazardous Substances Data Bank (HSDB)
- Solubility: 1.066 g/l water @ 18 °C Source: Hazardous Substances Data Bank (HSDB)
- Solubility: 20.55 g/l water @ 70 °C Source: Hazardous Substances Data Bank (HSDB)
- IARC Carcinogenic Agent: Molybdenum trioxide Source: International Agency for Research on Cancer (IARC)
- IARC Carcinogenic Classes: Group 2B: Possibly carcinogenic to humans Source: International Agency for Research on Cancer (IARC)
- IARC Monographs: Volume 118: (2018) Welding, Molybdenum Trioxide, and Indium Tin Oxide Source: International Agency for Research on Cancer (IARC)
- Publication Year: 2018 online Source: International Agency for Research on Cancer (IARC)
- Evaluation Year: 2017 Source: International Agency for Research on Cancer (IARC)
- Substance: Molybdenum Trioxide Source: NTP Technical Reports
- NTP Technical Report: TR-462: Toxicology and Carcinogenesis Studies of Molybdenum Trioxide (CASRN 1313-27-5) in F344 Rats and B6C3F1 Mice (Inhalation Studies) (1997 ) Source: NTP Technical Reports
- Peer Review Date: 12/05/95 Source: NTP Technical Reports
- Conclusion for Male Rat: Equivocal Evidence Source: NTP Technical Reports
- Conclusion for Female Rat: No Evidence Source: NTP Technical Reports
- Conclusion for Male Mice: Some Evidence Source: NTP Technical Reports
- Conclusion for Female Mice: Some Evidence Source: NTP Technical Reports
- First Aid: EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.; SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.; INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) shou Source: CAMEO Chemicals
- Signal: Warning Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
- GHS Hazard Statements: H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]; H351: Suspected of causing cancer [Warning Carcinogenicity] Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
- Precautionary Statement Codes: P203, P261, P264+P265, P271, P280, P304+P340, P305+P351+P338, P318, P319, P337+P317, P403+P233, P405, and P501 (click each P-code to see the statement) Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
- Signal: Warning Source: European Chemicals Agency (ECHA)
- GHS Hazard Statements: H319 (> 99.9%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H335 (> 99.9%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]; H351 (99.8%): Suspected of causing cancer [Warning Carcinogenicity] Source: European Chemicals Agency (ECHA)
- Precautionary Statement Codes: P203, P261, P264+P265, P271, P280, P304+P340, P305+P351+P338, P318, P319, P337+P317, P403+P233, P405, and P501 (click each P-code to see the statement) Source: European Chemicals Agency (ECHA)
- ECHA C&L Notifications Summary: Aggregated GHS information provided per 1297 reports by companies from 31 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
- Signal: Danger Source: NITE-CMC
- GHS Hazard Statements: H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]; H351: Suspected of causing cancer [Warning Carcinogenicity]; H361: Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]; H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]; H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure] Source: NITE-CMC
- Precautionary Statement Codes: P203, P260, P261, P264, P264+P265, P270, P271, P280, P304+P340, P305+P351+P338, P318, P319, P337+P317, P403+P233, P405, and P501 (click each P-code to see the statement) Source: NITE-CMC
- GHS Hazard Statements: H301: Toxic if swallowed [Danger Acute toxicity, oral]; H351: Suspected of causing cancer [Warning Carcinogenicity]; H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]; H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]; H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure] Source: NITE-CMC
- Precautionary Statement Codes: P203, P260, P264, P270, P280, P301+P316, P308+P316, P318, P319, P321, P330, P405, and P501 (click each P-code to see the statement) Source: NITE-CMC
- Consumer Uses: Catalyst; Corrosion inhibitor; Not Known or Reasonably Ascertainable; Intermediate; Alloys; Lubricating agent; Other Source: EPA Chemical Data Reporting (CDR)
- Industry Uses: Other; Lubricating agent; Alloys; Flame retardant; Corrosion inhibitor; Not Known or Reasonably Ascertainable; Catalyst; Intermediate Source: EPA Chemical Data Reporting (CDR)
- Sources/Uses: Used primarily in steel production as a corrosion inhibitor (~80-90%),then catalyst for refineries (~10%), then super alloys (~5%); [IARC Monograph 118] Used as a polymerization catalyst of olefins, a reagent in chemical analysis, a corrosion inhibitor, a catalyst in the petroleum industry, and an agricultural chemical; Also used to make molybdenum metal and alloys as well as ceramics, enamels, and pigments; [HSDB] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
- Industrial Processes with risk of exposure: Metal Preparation and Pouring [Category: Foundry]; Petroleum Production and Refining [Category: Industry]; Painting (Pigments, Binders, and Biocides) [Category: Paint] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
- Activities with risk of exposure: Ceramics making [Category: Hobbies]; Enameling [Category: Hobbies] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
- Uses: Pure molybdenum trioxide is used in chemical and catalyst manufacture and the technical product is added to steel as an alloying agent. Source: Hazardous Substances Data Bank (HSDB)
- Uses: To catalyze the polymerization of olefins Source: Hazardous Substances Data Bank (HSDB)
- Uses: Reagent in chem analysis Source: Hazardous Substances Data Bank (HSDB)
- Uses: MANUFACTURE OF MOLYBDENUM METAL & ALLOYS; CORROSION INHIBITOR; CATALYST IN PETROLEUM INDUSTRY; COMPONENT OF CERAMICS, ENAMELS & PIGMENTS; INTERMEDIATE FOR OTHER MOLYBDENUM CMPD Source: Hazardous Substances Data Bank (HSDB)
- Uses: AGRICULTURAL CHEMICAL Source: Hazardous Substances Data Bank (HSDB)
Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record
Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.
Additional source coverage and match status
| Source | Result | Checked |
|---|---|---|
| NIH PubChem PUG-View | Exact match | 2026-08-31 |
A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.
Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.