CHEMICAL SUBSTANCE DATASHEET
CHEMICAL SUBSTANCE IDENTIFICATION | |
Chemical name | Molybdenum |
Synonyms | Molybdenum metal |
IUPAC name | molybdenum |
CAS No | 7439-98-7 |
REACH registration number | pre-registered under REACH |
EC No | 231-107-2 |
Molecular formula | Mo |
Substance group/chemical family | mono-constituent /inorganic substance |
Appearance Physical state Odour Form Colour |
solid @ at 20°C and 1013 hPa [1] odourless [1] Powder (50%), Other (50%) metallic, black to silvery |
USES AND HANDLING ISSUES | |
Relevant identified uses | About 86% of molybdenum produced is used in metallurgy, with the rest used in chemical applications. The estimated global use is structural steel 35%, stainless steel 25%, chemicals 14%, tool & high-speed steels 9%, cast iron 6%, molybdenum elemental metal 6%, and superalloys 5%. Molybdenum powder is used as a fertilizer for some plants, such as cauliflower. Elemental molybdenum is used in NO, NO2, NOx analyzers in power plants for pollution controls. At 350 °C, the element acts as a catalyst for NO2/NOx to form NO molecules for detection by infrared light. Molybdenum anodes replace tungsten in certain low voltage X-ray sources for specialized uses such as mammography. The radioactive isotope molybdenum-99 is used to generate technetium-99m, used for medical imaging. The isotope is handled and stored as the molybdate [2]. |
Handling considerations | Storage: Avoid formation of dust. Observe national and regional provisions in force. Store away from incompatible substances (Bromine Pentafluoride: violent reaction which may ignite, Chlorine Trifluoride: violent reaction that may ignite, Lithium: reacts, Magnesium: when heated a violent detonation may occur, Potassium: reacts with incandescence, Sodium: reacts violently). [1] |
PHYSICO-CHEMICAL PROPERTIES | |
Molecular weight | 95.95 g/mol [3] |
Bulk density/Specific gravity | 10.18 g/cm3 @ 20°C [1] |
pH |
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Particle size |
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EC |
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Melting point | 2 623 °C [1] |
Boiling point | 4 639 °C @ 101 325 Pa [1] |
Flash point |
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Flammability | non flammable [1] |
Vapour density |
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Vapour pressure |
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Solubility in water | 5.5 - 12 mg/L @ 20 °C and pH 3.5 - 4.3 [1] |
Solubility in organic solvents |
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Solubility in inorganic solvents |
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Hydrolysis |
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Ionicity in water |
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Surface tension |
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Dispersion properties |
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Specific surface |
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Stability and reactivity | |
Chemical stability |
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Reactivity hazards |
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Corrosivity |
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Polimerization |
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Incompatibility with various substances | Bromine Pentafluoride: violent reaction which may ignite, Chlorine Trifluoride: violent reaction that may ignite, Lithium: reacts, Magnesium: when heated a violent detonation may occur, Potassium: reacts with incandescence, Sodium: reacts violently [1] |
Special remarks on reactivity |
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Physical, chemical and biological coefficient | |
Koc |
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Kow |
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pKa |
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log Kp | water-sediment log Kd: 3.48 (3,020 L/kg) [1] |
Henry-constant |
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ENVIRONMENTAL FATE AND BEHAVIOUR | |
Artificial pollution sources |
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General terrestrial fate |
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General aquatic fate |
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General atmospheric fate |
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General persistence and degradability |
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Abiotic degradation and metabolites |
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Biodegradation and metabolites |
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Bioconcentration | molybdenum did not biomagnify in aquatic food chains [1] |
Volatilization |
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Photolysis |
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Hydrolysis |
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Soil adsorption and mobility |
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ENVIRONMENTAL CONCENTRATIONS | |
Measured data | The regional (EU) ambient reasonable-worst-case concentration of dissolved molybdenum in european surface waters is 2.30 µg/L [1] |
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ECOTOXICOLOGICAL INFORMATION | |
General adverse effects on ecosystem | |
Acute toxicity (LC50, EC50) | |
Aquatic systems | LC50 (4 days) 609.1 - 681.4 mg/L (fish) [1] LC50 (48 h) 1.006 - 2.729 g/L (aquatic inverterbrates) [1] EC50 (48 h) 130.9 - 2 847.5 mg/L (aquatic inverterbrates) [1 EC50 (72 h) 218 - 2 453.6 mg/L (aquatic algae and cyanobacteria) [1] EC50 (7 days) 890.2 - 1 190 mg/L, (aquatic plants other than algae) [1] EC50 (3 h) 820 mg/L, (microorganisms) [1] EC50 (30 min) 1.1 g/L, (microorganisms) [1]
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Terrestrial systems |
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Chronic toxicity (NOEC, LOEC) | |
Aquatic systems | NOEC (84 days) 121 - 294.9 mg/L (fish) (Mo, as sodium molybdate) [1] NOEC (78 days) 48.9 - 152.7 mg/L (fish) [1] NOEC (37 days) 139 - 1 070 mg/L (fish) [1] NOEC (34 days) 27.7 - 203.5 mg/L (fish) [1] NOEC (28 days) 63 - 444.3 mg/L (fish) [1] NOEC (48 h) 1.653 g/L (aquatic inverterbrates) [1] NOEC (30 days) 79 mg/L, (aquatic inverterbrates) [1] NOEC (28 days) 116 mg/L, (aquatic inverterbrates) [1] NOEC (21 days) 49.9 - 377 mg/L, (aquatic inverterbrates) [1] NOEC (20 days) 26 mg/L, (aquatic inverterbrates) [1] NOEC (14 days) 393 - 1 564 mg/L, (aquatic inverterbrates) [1] NOEC (72 h) 27 - 938 mg/L (aquatic algae and cyanobacteria) [1] LOEC (72 h) 310 - 938 mg/L, (aquatic algae and cyanobacteria) [1] EC10 (72 h) 61.2 - 881 mg/L, (aquatic algae and cyanobacteria) [1] NOEC (7 days) 24.7 - 641 mg/L, (aquatic plants other than algae) [1] LOEC (7 days) 51.7 - 1 190 mg/L, (aquatic plants other than algae) [1] EC10 (7 days) 241.5 - 274 mg/L, (aquatic plants other than algae) [1] EC10 (3 h) 216.5 - 325 mg/L, (microorganisms) [1]
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Terrestrial systems | NOEC (56 days) 7.88 - 77.9 mg/kg soil dw, (terrestrial macroorganisms except arthropods) [1] EC10 (56 days) 8.21 - 6 307 mg/kg soil dw, (terrestrial macroorganisms except arthropods) [1] EC10 (28 days) 67.2 - 3 040 mg/kg soil dw, (terrestrial macroorganisms except arthropods) [1] EC10 (28 days) 37.9 - 7 285 mg/kg soil dw, (terrestrial arthropods) [1] EC10 (21 days) 0.4 - 3 476 mg/kg soil dw, (terrestrial plants) [1] EC10 (4 days) 3 - 869 mg/kg soil dw, (terrestrial plants) [1] EC10 (28 days) 35 - 10 000 mg/kg soil dw, (soil microorganisms) [1] EC10 (24 h) 1 - 10 000 mg/kg soil dw, (soil microorganisms) [1] NOEC (28 days) 400 mg/kg diet (birds) [1] LOEC (28 days) 500 mg/kg diet, (birds) [1] |
HUMAN HEALTH EFFECTS and PROTECTION | |
Routes of human exposures | inhalation, oral |
General effects |
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Endocrine disruption |
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Mutagenicity |
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Carcinogenicity |
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Reprotoxicity |
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Teratogenicity |
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Skin, eye and respiratory irritations |
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Metabolism: absorption, distribution & excretion |
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Exposure limits | (DNEL) 11.7 mg/m³ (repeated dose toxicity, inhalation, workers) [1] (DNEL) 3.33 mg/m³ (repeated dose toxicity, inhalation, general population) [1] (DNEL) 3.4 mg/kg bw/day (repeated dose toxicity, oral, general population) [1] |
Drinking water MAC |
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Other information |
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Animal toxicity data | |
Acute toxicity (LD50) | LD50 2 000 - 5 000 mg/kg bw (rat) (oral) [1] LC50 (4 h) 1.93 - 5.84 mg/L air (rat) (inhalation) [1] LD50 2 000 mg/kg bw (rat) (dermal) [1] |
Chronic toxicity (NOEL, LOEL) | NOAEL (rat): 17 - 60 mg/kg bw/day (oral) [1] NOAEC (rat): 100 mg/m³ air (inhalation) [1] NOAEC (mouse): 100 mg/m³ air (inhalation) [1] LOEC (mouse): 30 - 100 mg/m³ air (inhalation) [1] |
ENVIRONMENTAL STANDARDS AND REGULATIONS | |
EINECS regulation | ̵EINECS (European INventory of Existing Commercial chemical Substances) List |
OSHA regulations etc. |
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OTHER INFORMATION, SPECIAL REMARKS | |
Classification and proposed labelling with regard to toxicological data | No signal word ECHA has no data from registration dossiers on the precautionary measures for using this substance. Additionally, the classification provided by companies to ECHA in CLP notifications identifies that this substance is a flammable solid, is suspected of damaging fertility or the unborn child and is a highly flammable liquid and vapour. [1] |
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CREATED, LAST UPDATE | |
Created | 2018. 11. 06. |
Last update | 2018. 11. 07 |
REFERENCES [1] ECHA https://echa.europa.eu/registration-dossier/-/registered-dossier/15524/1, Accessed 06. November, 2018 [2] Wikipedia, molybdenum: https://en.wikipedia.org/wiki/Molybdenum, Accessed 07. November, 2018 [3] Commission on Isotopic Abundances and Atomic Weights. http://www.ciaaw.org/molybdenum.htm, Accessed 07. November, 2018 | |