Periodic Table

Molybdenum

Transition Metal

Quick Facts about Molybdenum

Nb
  • solid- state of matter at room temperature
  • Stable- has at least one stable isotope
  • +6- common oxidation states in compounds
  • BCC- crystal structure, atomic arrangement in solid form
Tc

Molybdenum (Mo) is element 42 on the periodic table. Atomic mass of Mo: 95.9500 u. Mo is in period 5, group 6. Melting point of Mo: 2896.00 K.Density of Mo: 10.28 g/cm³.

Why Molybdenum Matters

Molybdenum in everyday life and industry

In Your Home

  • Catalytic converters in cars use molybdenum compounds
  • Lubricants for extreme conditions often contain molybdenum disulfide

Industry Uses

MetallurgyHigh-strength steel for bridges and buildings contains molybdenum
MetallurgyStainless steel cutlery typically contains 0.5-1% molybdenum

In Your Body

✓ Essential for life

Molybdenum is essential for humans - we need about 45 micrograms daily The enzyme xanthine oxidase (involved in gout) requires molybdenum Nitrogen-fixing bacteria absolutely require molybdenum Molybdenum deficiency is extremely rare due to its wide presence in foods

Safety: No significant toxicity data for Molybdenum.

Discovery of Molybdenum

Discovered by Carl Wilhelm Scheele in Sweden, 1778

Name origin: Greek: molybdos (lead).

History & Events

1778
Name comes from Greek 'molybdos' meaning 'lead-like'
1778
Confused with graphite and lead ore for centuries
1778
Carl Wilhelm Scheele identified it as distinct in 1778
1778
Became strategically important in WWI for armor-piercing shells

About Molybdenum

Silvery-white, hard metallic transition element. It is chemically unreactive and is not affected by most acids. It oxidizes at high temperatures. There are seven natural isotopes, and four radioisotopes, Mo-93 being the most stable with a half-life of 3500 years. Molybdenum is used in almost all high-strength steels, it has nuclear applications, and is a catalyst in petroleum refining. Discovered in 1778 by Carl Welhelm Scheele of Sweden. Impure metal was prepared in 1782 by Peter Jacob Hjelm. The name comes from the Greek word molybdos which means lead. Trace amounts of molybdenum are required for all known forms of life. All molybdenum compounds should be considered highly toxic, and will also cause severe birth defects.

Atomic Properties of Mo

Atomic Number of Mo
42
Atomic Mass of Mo
95.9500 u
Electron Configuration
[Kr] 4d5 5s1
Electronegativity
2.16
Block
d-block
Group
6
Period
5

Physical Properties of Mo

Phase (STP)
solid
Melting Point of Mo
2896.00 K
Boiling Point of Mo
4912.00 K
Density of Mo
10.2800 g/cm3

Thermal Properties

Heat of Fusion
28.00 kJ/mol
Heat of Vaporization
590.00 kJ/mol
Specific Heat
0.25 J/g·K
Molar Heat Capacity
24.06 J/mol·K

Atomic Radii

Calculated
145 pm
Covalent
138 pm
Van der Waals
217 pm
Metallic
130 pm

Common Misconceptions

Wrong:Molybdenum is similar to lead because of its name.
Correct:Despite its name meaning 'lead-like' (from Greek molybdos), molybdenum is chemically nothing like lead—it's a transition metal with very different properties.
Wrong:Molybdenum is just an industrial metal with no biological role.
Correct:Molybdenum is essential for human health—it's required for enzymes like xanthine oxidase and sulfite oxidase.
Wrong:'Moly' grease works by being inherently slippery.
Correct:MoS2 grease works through its layered crystal structure—sheets slide over each other like a deck of cards.

Isotopes of Molybdenum

Molybdenum has 7 naturally occurring isotopes.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
9242Mo (Mo-92)Molybdenum-92 isotope91.9068079614.53%——
9442Mo (Mo-94)Molybdenum-94 isotope93.90508499.150%——
9542Mo (Mo-95)Molybdenum-95 isotope94.9058387715.84%——
9642Mo (Mo-96)Molybdenum-96 isotope95.9046761216.67%——
9742Mo (Mo-97)Molybdenum-97 isotope96.906018129.600%——
9842Mo (Mo-98)Molybdenum-98 isotope97.9054048224.39%——
10042Mo (Mo-100)Molybdenum-100 isotope99.90747189.820%——

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Molybdenum have important real-world applications in science and industry.

Industrial Applications

Depleted 95Mo has been used in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (Tennessee, USA). The use of U-10Mo fuel elements (90 percent uranium, 10 percent molybdenum) would allow the conversion from high-enrichment uranium (HEU) fuel, 92 percent, to low-enrichment uranium (LEU) fuel, below 20 percent, for nuclear non-proliferation purposes [319].

Abundance

Earth's Crust
1.2 mg/kg
Seawater
10.00 μg/kg

Uses

Its alloys are used in aircraft, missiles, and protective coatings in boiler plate.

Sources

Found in the minerals molybdenite (MoS2) and wulfenite (MoO4Pb).

Geochemistry

Goldschmidt
siderophile

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