Molybdenum

CAS ID #: 7439-98-7

Affected Organ Systems: Hepatic (Liver), Renal (Urinary System or Kidneys), Reproductive (Producing Children), Respiratory (From the Nose to the Lungs)

Cancer Classification: EPA: Not classifiable as to human carcinogenicity. IARC: Not classifiable as to carcinogenicity to humans. NTP: Not evaluated

Please contact NTP, IARC, or EPA’s IRIS Hotline with questions on cancer and cancer classification.

Chemical Classification: Metals/Elements (the simplest forms of matter)

Summary: 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.