Molybdenum

95.96000

97.90540

231-107-2

81AH48963U

1003

3089

DTXSID1024207

C666

Dark-gray or black powder with metallic luster or coherent mass of silver white color; body centered cubic structure|Very hard, but more ductile that the chemically similar element tungsten|Gray-black metal, cubic

81029600

0

0.00000

MOLYBDENUM, a chemical element, is a hard, high-melting (refractory) high-density dark gray metal or black powder. Insoluble in water. Used to make structural alloys; used as a catalyst. Molybdenum dust and fumes can irritate the eyes and respiratory tract.

10.28 g/cm³

2622 °C

4825 °C (approx)

-23ºC

2.81 (740 nm)

H2O: soluble

Flammables area

0 mmHg (approx)

Combustible Solid in form of dust or powder.

Metallic molybdenum is a combustible solid in the form of dust or powder and is potentially explosive.

Naturally occurring isotopes: 98 (23.75 % abundance); 96 (16.5 %); 95 (15.7%); 92 (15.86%); 94 (9.12%); 100 (9.62%); 97 (9.45%)|Completely miscible with niobium and tantalum and with the high-temperature form of titanium; resistant to acid attack by HF and HCl|Molar heat capacity: 24.06 J/mol K at 25 °C, 100 kPa (760 mm Hg)|Standard enthalpy of formation (gas): 658.1 kJ/mol|For more Other Experimental Properties (Complete) data for MOLYBDENUM (10 total), please visit the HSDB record page.

No rapid reaction with air No rapid reaction with water

Metals, Less Reactive

Strong Reducing Agent

MOLYBDENUM is a reducing agent. In dust or powder form, it may present a fire or explosion hazard under favoring conditions of particle size, dispersion and ignition. Bulk molybdenum (rod, coil, sheet, etc.) is less reactive than dust or powder. Insoluble in hydrochloric acid or hydrofluoric acid solutions and in ammonia and sodium hydroxide solutions. Insoluble in dilute sulfuric acid solutions but soluble in concentrated sulfuric acid. Soluble in concentrated nitric acid. Incompatible with strong oxidizing agents such as bromine trifluoride, bromine pentafluoride, chlorine trifluoride, potassium perchlorate, nitryl fluoride, fluorine, iodine pentafluoride, sodium peroxide, lead dioxide.

Combustible Solid in form of dust or powder.

Dust explosion possible if in powder or granular form, mixed with air.

491 kJ/mol

III

4.1

UN 3264 8/PG 3

3

R36/37/38

S24/25

QA4680000

Xi

Separated from strong oxidants, halogens and strong acids.

Stable. Powder is flammable.

P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501

H315

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.|Recovery is indicated whenever possible. Processes for recovery of molybdenum from scrap, flue dusts, spent catalysts, and other industrial wastes have been developed.|The following wastewater treatment technologies have been investigated for molybdenum: Chemical precipitation.

Soluble compounds: alkali metals, sodium, potassium, molten magnesium. Insoluble compounds: Violent reactions with oxidizers, nitric acid, sulfuric acid. ...|Chlorine trifluoride acts on powdered molybdenum with incandescence.|Fluorine acts on powdered molybdenum with incandescence. Other interhalogen compounds containing fluorine may act similarly.|Powdered molybdenum mixed with lead dioxide becomes incandescent when heated.|For more Hazardous Reactivities and Incompatibilities (Complete) data for MOLYBDENUM (6 total), please visit the HSDB record page.

USEPA, Office of Drinking Water; Criteria Document (Draft): Molybdenum (1985)|Nat'l Research Council Canada; Data Sheets on Selected Toxic Elements (1982) NRCC No. 19252

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]: May react violently or explosively on contact with water. Some are transported in flammable liquids. May be ignited by friction, heat, sparks or flames. Some of these materials will burn with intense heat. Dusts or fumes may form explosive mixtures in air. Containers may explode when heated. May re-ignite after fire is extinguished. (ERG, 2016)|Combustible under specific conditions. Finely dispersed particles form explosive mixtures in air.

|Danger|H225 (27.24%): Highly Flammable liquid and vapor [Danger Flammable liquids]|P201, P202, P210, P233, P240, P241, P242, P243, P280, P281, P303+P361+P353, P308+P313, P370+P378, P403+P235, P405, and P501|Aggregated GHS information provided by 1445 companies from 11 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|Warning|H315: Causes skin irritation [Warning Skin corrosion/irritation]|P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, and P501|H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]|P261, P271, P304+P340, P312, P403+P233, P405, and P501

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]: DO NOT USE WATER, FOAM OR CO2. Dousing metallic fires with water will generate hydrogen gas, an extremely dangerous explosion hazard, particularly if fire is in a confined environment (i.e., building, cargo hold, etc.). Use DRY sand, graphite powder, dry sodium chloride-based extinguishers, G-1® or Met-L-X® powder. Confining and smothering metal fires is preferable rather than applying water. Move containers from fire area if you can do it without risk. FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: If impossible to extinguish, protect surroundings and allow fire to burn itself out. (ERG, 2016)|In case of fire in the surroundings, use appropriate extinguishing media.

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]: As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. LARGE SPILL: Consider initial downwind evacuation for at least 50 meters (160 feet). FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]: ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2016)

Skin: No recommendation is made specifying the need for personal protective equipment for the body. Eyes: No recommendation is made specifying the need for eye protection. Wash skin: No recommendation is made specifying the need for washing the substance from the skin (either immediately or at the end of the work shift). Remove: No recommendation is made specifying the need for removing clothing that becomes wet or contaminated. Change: No recommendation is made specifying the need for the worker to change clothing after the work shift. (NIOSH, 2016)|Wear protective gloves and clothing to prevent any reasonable probability of skin contact. Safety equipment suppliers/manufacturers can provide recommendations on the most protective glove/clothing material for your operation. All protective clothing (suits, gloves, footwear, headgear) should be clean, available for work each day, and put on before work. Contact lenses should not be worn when working with this chemical. Wear eye protection (chemical goggles and face shield unless full face-piece respiratory protection is worn). Employees should wash immediately with soap when skin is wet or contaminated.|Respirators may be used when engineering and work practice controls are not technically feasible, when such controls are in the process of being installed, or when they fail and need to be supplemented. Respirators may also be used for operations which require entry into tanks or closed vessels, and in emergency situations. If the use of respirators is necessary, the only respirators permitted are those that have been approved by the Mine Safety and Health Administration (formerly Mining Enforcement and Safety Administration) or by the National Institute for Occupational Safety and Health. /Soluble Molybdenum cmpd (as Molybdenum); Molybdenum and insoluble molybdenum cmpd/|Respirator Recommendations: Up to 75 mg/cu m: [Table#5057]|Respirator Recommendations: Up to 150 mg/cu m: [Table#5058]|For more Personal Protective Equipment (PPE) (Complete) data for MOLYBDENUM (9 total), please visit the HSDB record page.|(See protection codes)

FLAMMABLE IN FORM OF DUST OR POWDER.

Metallic molybdenum is a combustible solid in the form of dust or powder and is potentially explosive.

Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Use HEPA vacuum or wet method to reduce dust during clean-up. Do not dry sweep. Collect powdered material in the most convenient and safe manner and deposit in sealed containers. Ventilate area after clean-up is complete. It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Contact your Department of Environmental Protection or your regional office of the federal EPA for specific recommendations. If employees are required to clean up spills, they must be properly trained and equipped. OSHA 1910.120(q) may be applicable.

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.|... A complete respiratory protection program should be instituted which incl regular training, maintenance, inspection, cleaning, and evaluation. /Sol Molybdenum compounds (as Mo); Molybdenum and insoluble molybdenum compounds/

Contact irritates the skin and eyes. Inhalation can irritate the respiratory tract ...|Fume from arcing molybdenum metal causes respiratory irritation in animals.

After reviewing available published literature, NIOSH provided comments to OSHA on August 1, 1988, regarding the "Proposed Rule on Air Contaminants" (29 CFR 1910, Docket No. H-020). In these comments, NIOSH questiones wheher the PEL proposed for molybdenum (soluble compounds as Mo) [TWA 5 mg/cu m] was adequate to protect workers from recognized health hazards.

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting.

Separated from strong oxidants, halogens and strong acids.

Closed system, dust explosion-proof electrical equipment and lighting. Prevent deposition of dust.

PREVENT DISPERSION OF DUST!

Use local exhaust or breathing protection.

Protective gloves.

Wear safety spectacles.

Molybdenum is a chemical element with the symbol Mo. Pure molybdenum exists as a dark-gray or black powder with a metallic luster or as a silvery-white mass. It does not occur naturally in the pure metallic form. It is principally found as oxide or sulfide compounds. Therefore, almost all exposure is to a molybdenum compound rather than the actual metal alone. Important naturally occurring molybdenum compounds are the minerals molybdenite, powellite, wulfenite, ferrimolybdite, and ilsemannite. Molybdenum has a very high melting point and it is used widely in industry to make steel alloys.

In persons with impaired pulmonary function, especially those with obstructive airway diseases, the breathing of insoluble molybdenum compounds might cause exacerbation of symptoms due to their irritant properties. /Molybdenum and insoluble molybdenum compounds/

A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) (See all compounds classified as Trace Elements.)

The chronic inhalation of molybdenum dusts (57 mg molybdenum/cu m during 120 days, 4 hr/day) in rats showed a high accumulation of molybdenum in lung, spleen, and heart and a decrease of DNA and RNA levels in liver, kidneys, and spleen. /Molybdenum dusts/

Impurities: trace metals, potassium, sodium.|Impurities: Carbon, oxygen, nitrogen, iron, nickel, silicon.

Exposure Routes: inhalation, ingestion, skin and/or eye contact Target Organs: Eyes, respiratory system, liver, kidneys (NIOSH, 2016)

Eye: If this chemical contacts the eyes, immediately wash the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Contact lenses should not be worn when working with this chemical. Breathing: If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform mouth-to-mouth resuscitation. Keep the affected person warm and at rest. Get medical attention as soon as possible. Swallow: If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2016)|(See procedures)

Fresh air, rest.

Rinse skin with plenty of water or shower.

Rinse with plenty of water for several minutes (remove contact lenses if easily possible).

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/|Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/|Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

/SIGNS AND SYMPTOMS/ Metallic and poorly soluble molybdenum compounds (such as molybdenum disulfide, molybdenum dioxide) have limited animal experimental data and no human toxicity data. From the scant information available, these materials thought to be poorly soluble and to have low animal and human toxicity. Until toxicologic or human data indicate a more serious threat to human health, these materials are assigned TLV-TWAs of 10 mg/m3 (inhalable particulate mass) and 3 mg/m3 (respirable particulate mass) to protect against any irritant effects of these materials. /Metallic molybdenum and poorly soluble molybdenum/|/SIGNS AND SYMPTOMS/ Pneumoconiosis with X-ray findings and subjective symptoms ... reported in 3 out of 19 workers exposed to metallic molybdenum and molybdenum trioxide. Exposure varied between 1 and 19 mg/cu m for 4 to 7 yr. /Metallic molybdenum and molybdenum trioxide/|/SIGNS AND SYMPTOMS/ Increased blood uric acid values and gout-like symptoms have been reported among workers exposed to molybdenum in a copper-molybdenum plant ... . /Molybdenum and compounds/|/SIGNS AND SYMPTOMS/ In a 1984 review, an increased incidence of nonspecific symptoms, including weakness, fatigue, headache, anorexia, and joint and muscle pains, was reported among mining and metallurgy workers exposed at 60 to 600 mg/cu m molybdenum /Molybdenum dusts/|For more Human Toxicity Excerpts (Complete) data for MOLYBDENUM (7 total), please visit the HSDB record page.

Molybdenum

inhalation, ingestion, skin and/or eye contact

In Animals: irritation eyes, nose, throat; anorexia, diarrhea, weight loss; listlessness; liver, kidney damage

Cough.

Redness.

Reproductive (Producing Children), Respiratory (From the Nose to the Lungs)|Eyes, respiratory system, liver, kidneys

End use applications: Machinery, 35%; oil and gas industry, 20%; transportation, 15%; chemicals, 15%; electrical, 10%; and other, 5% (1986)|End use applications: Machinery, 35%; oil and gas industry, 10%; transportation, 15%; chemicals, 10%; electrical, 15%; and other, 15% (1988)|Molybdenum consumption statistics for the United States.

Grade: Rods and wire 99.9%, powder 99.9%.|Ingots, rods, wire, powder, ingots (from powder); high ductility sheets, concentrates; also as large single crystal.|Arc-cast material, 99.931-99.961% min Molybdenum; Powder-metallurgy material, 99.956% min Molybdenum

Computer and electronic product manufacturing|Molybdenum: ACTIVE|Molybdenum ore was produced as a primary product at three mines, one each in Colorado, Idaho, and New Mexico, whereas six copper mines (two in Arizona, one each in Montana, Nevada, New Mexico, and Utah) recovered molybdenum as a byproduct.|... Obtained principally from molybdenite. Wulfenite & Powellite are also minor commercial ores. Molybdenum is also recovered as a by product of copper and tungsten mining operations.

Direct Aspiration Atomic Absorption Spectrometry is used for the determination of molybdate. Using nitrous oxide acetylene as the flame gas at a wavelength of 313.3 nm, the detection limit is 0.1 mg/l, with a sensitivity of 0.5 mg/l, at an optimum concentration range of 1-20 mg/l. /Total molybdenum/|Analysis (detection limit): polarography: 0.01 mg Mo/kg colorimetry (thiocyanate): 0.1 mg Mo/kg neutron activation: 3 ng atomic absorption (N2O/C2 H2 flames): 0.02 mg Mo/l plasma-emission spectrometry: 0.002 mg Mo/kg spark-source mass spectrometry: 0.3 ng. /Total molybdenum/|Method: NIOSH 7300, Issue 3; Procedure: inductively coupled argon plasma, atomic emission spectroscopy (nitric/perchloric acid ashing); Analyte: molybdenum; Matrix: air; Detection Limit: 0.8 ng/mL.|Method: NIOSH 7303, Issue 1; Procedure: inductively coupled argon plasma, atomic emission spectroscopy (hot block/HCl/Hno3 digestion); Analyte: molybdenum; Matrix: air; Detection Limit: 0.0072 ug/mL.|For more Analytic Laboratory Methods (Complete) data for MOLYBDENUM (24 total), please visit the HSDB record page.

Method: USGS-NWQL B-9001-95; Procedure: inductively coupled plasma - atomic emission spectrometry; Analyte: molybdenum; Matrix: aquatic biological tissue and aquatic plant material; Detection Limit: not provided.|Method: USGS-NWQL B-9001-95; Procedure: inductively coupled plasma - mass spectrometry; Analyte: molybdenum; Matrix: aquatic biological tissue and aquatic plant material; Detection Limit: 0.01 ug/g.

Chemical Classes -> Metals/Elements (the simplest forms of matter)