Molybdenum

Molybdenum (Mo)

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 Number42
Atomic Weight95.95
Mass Number98
Group6
Period5
Blockd
Protons42 p+
Neutrons56 n0
Electrons42 e-
Molybdenum crystaline fragment and 1cm3 cube.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
145 pm
Atomic Volume
Covalent Radius
138 pm
Metallic Radius
130 pm
Ionic Radius
69 pm
Crystal Radius
83 pm
Van der Waals radius
217 pm
Density
10.2 g/cm³
Boiling Point
4,885 K
Melting Point
2,890 K
Electrons per shell2, 8, 18, 13, 1
Electronegativity
2.16
Electrophilicity
1.2111478608973 eV/particle
Proton Affinity
Electron Affinity
Ionization Potential
7.09243 eV/particle
Heat of Vaporization
590 kJ/mol
Heat of Fusion
Heat of Formation
658.98 kJ/mol
Molar Heat Capacity
24.06 J/(mol K)
Specific Heat Capacity
0.251 J/(g⋅K)
Thermal Conductivity
Gas Basicity
Dipole Polarizability
87 a₀
C6 Dispersion Coefficient
Oxidation States-2, -1, 1, 2, 3, 4, 5, 6
Color
Gray
Crystal StructureBody Centered Cubic (BCC)
Lattice Constant
3.15 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Kr] 4d5 5s1
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryTransition metals, Transition metals
CAS GroupVIA
IUPAC GroupVIB
Glawe Number56
Mendeleev Number52
Pettifor Number55
Geochemical Class
Goldschmidt Classsiderophile
Radioactivity
RadioactiveNo
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
1.2 mg/kg
Abundance in Oceans
0.01 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe5×10-7%

Isotopes of Molybdenum

Stable Isotopes
92Mo 94Mo 95Mo 96Mo 97Mo 98Mo 100Mo
Unstable Isotopes
83Mo 84Mo 85Mo 86Mo 87Mo 88Mo 89Mo 90Mo 91Mo 93Mo 99Mo 101Mo 102Mo 103Mo 104Mo 105Mo 106Mo 107Mo 108Mo 109Mo 110Mo 111Mo 112Mo 113Mo 114Mo 115Mo

History

Molybdenite was often confused for graphite and it was thought to contain lead. In 1778 Swedish scientist Carl Wilhelm Scheele proved that molybdenite was not graphite nor did it contain lead. In 1781, Scheele's friend and countryman, Peter J. Hjelm isolated the metal by using carbon and linseed oil. From the Greek word molybdo, lead

DiscoverersCarl Wilhelm Scheele
Discovery LocationSweden
Discovery Year1778
Name OriginGreek: molybdos (lead).
Molybdenum is toxic in all but small quantities
Molybdenum is essential for plant foliage health

Uses

Molybdenum is used as glass furnace electrodes due to its high melting point. The metal is also used in nuclear energy applications and for missile and aircraft parts. Molybdenum is valuable as a catalyst in the refining of petroleum. Molybdenum is used in small quantities to harden steel and is used in many alloys. Its alloys are used in aircraft, missiles, and protective coatings in boiler plate.

Sources

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