Molybdenum Silicide









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Product Name:     Molybdenum Silicide

Formula:              MoSi2

CAS Number:       12136-78-6




Hazardous Components:  Molybdenum Silicide

Percent (%):                    0-100

OSHA/PEL:                       10 mg(Mo)/m3

ACGIH/TLV:                      10 mg(Mo)/m3

HMIS Rating:

Health:                             2

Flammability:                  0

Reactivity:                       0




Boiling Point:                   N/A or N/E

Melting Point:                  1870 oC

Specific Gravity:              6.31 g/cc

Solubility in H2O:             Insoluble

Appearance and Odor:    Gray-black powder and pieces, no odor.




Flash Point:  N/A

Flammability:  Non-flammable

Autoignition Temperature:  N/A

Explosive LimitsLower:  N/A         Upper:  N/A

Extinguishing Media:  Use suitable extinguishing media for surrounding materials and type of fire.

Special Firefighting Procedures:  Firefighters must wear a self-contained breathing apparatus and full protective clothing to prevent contact with skin and eyes.

Unusual Fire and Explosion Hazards:  When heated to decomposition, molybdenum silicide may emit toxic fumes of molybdenum and silicon.  Molybdenum silicide may emit flammable hydrogen gas on contact with acids.




Effects of Exposure:

To the best of our knowledge the chemical, physical and toxicological properties of molybdenum silicide have not been thoroughly investigated and recorded.

Molybdenum and it’s compounds are highly toxic based upon animal experiments.  Symptoms of acute poisoning include severe gastrointestinal irritation with diarrhea, coma, and deaths from heart failure.  Experimental animals exposed to high levels accumulated molybdenum in the lungs, spleen, and heart, and showed a decrease of DNA and RNA in the liver, kidneys, and spleen. (Sax, Dangerous Properties of Industrial Materials)

Inorganic silicon compounds may be acute inhalation irritants.  Prolonged inhalation may cause pulmonary fibrosis known as silicosis.

Acute Effects:

Inhalation:  May cause irritation to the upper respiratory system.

Ingestion:  May cause acute molybdenum poisoning.

Skin:  Prolonged or repeated contact may cause irritation.

Eye:  Prolonged or repeated contact may cause irritation.

Chronic Effects:

Inhalation:  May cause pneumoconiosis.

Ingestion:  May cause chronic molybdenum poisoning.

Skin:  No chronic health effects recorded.

Eye:  No chronic health effects recorded.

Medical Conditions Generally Aggravated by Exposure:  Pre-existing respiratory disorders.

CarcinogenicityNTP:  No      IARC:  No    OSHA:  No



INHALATION:  Remove to fresh air, keep warm and quiet, give oxygen if breathing is difficult and seek medical attention.

INGESTION:  Give 1-2 glasses of milk or water and induce vomiting, seek medical attention.  Never induce vomiting or give anything by mouth to an unconscious person.

SKIN:  Remove contaminated clothing, brush material off skin, wash area with soap and water, seek medical attention if symptoms persist.

EYES:  Flush eyes with lukewarm water, including under upper and lower eyelids, for at least 15 minutes.  Seek medical attention if symptoms persist.




Stability:  Stable

Conditions to Avoid:  None

Incompatibility (Material to Avoid):  Acids, interhalogens, strong oxidizing agents.

Hazardous Decomposition Products:  Fumes of molybdenum, molybdenum oxide, silicon oxide, and hydrogen.

Hazardous Polymerization:  Will not occur




Steps to Be Taken in Case Material Is Released or Spilled:  Wear appropriate respiratory and protective equipment specified in section VIII.  Isolate spill area and insure proper ventilation.  Vacuum up the spill using a high efficiency particulate absolute (HEPA) unit and place in a container for proper disposal.  Take care not to raise dust.

Waste Disposal Method:  Dispose of in accordance with all Local, State, and Federal regulations.






Respiratory Protection:  Wear NIOSH-approved dust-mist-fume cartridge respirator.

Ventilation:  Use local exhaust to maintain exposure below TLV.  General exhaust is recommended.

Protective Gloves:  Rubber glove

Eye Protection:  Safety Glasses

Other Protective Clothing or Equipment:  Wear protective clothing to prevent contamination of skin and clothes.




Precautions to Be Taken in Handling and Storage:  Store in tightly closed containers in a cool, dry place.  Wash hands and face thoroughly after handling and before meals.

Work Practices:  Implement engineering and work practice controls to reduce and maintain concentration of exposure at low levels.  Use good housekeeping and sanitation practices.  Do not use tobacco or food in work area.  Wash thoroughly before eating and smoking.  Do not blow dust off clothing or skin with compressed air.  Maintain eyewash capable of sustained flushing, safety drench shower and facilities for washing.

TSCA Listed:       Yes

DOT Regulations:

Hazard Class:     None



The above information is believed to be correct, but does not purport to be all inclusive and shall be used only as a guide.  ESPI shall not be held liable for any damage resulting from handling or from contact with the above product.


Issued by:             S. Dierks

Dated:                  October 2007

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