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Periodic Table of Elements

Element Molybdenum – Mo

Comprehensive data on the chemical element Molybdenum is provided on this page; including scores of properties, element names in many languages, most known nuclides of Molybdenum. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one studies. Using the "Periodic Table of Elements Quick Navigation" graphic at the bottom of the sidebar menu, one can quickly jump from chemical element to chemical element.

Molybdenum Menu

• Molybdenum Page One
  • Overview of Molybdenum
  • Molybdenum's Name in Other Languages
  • Atomic Structure of Molybdenum
  • Chemical Properties of Molybdenum
  • Physical Properties of Molybdenum
  • Regulatory / Health
  • Who/When/Where/How
• Molybdenum Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Molybdenum Page Three
  • Common Chemical Compounds of Molybdenum

Overview of Molybdenum

• Atomic Number:42
• Group: 6
• Period: 5
• Series: Transition Metals

Molybdenum's Name in Other Languages

• Latin: Molybdaenum
• Czech: Molybden
• Croatian: Molibden
• French: Molybdéne
• German: Molybdän - r
• Italian: Molibdeno
• Norwegian: Molybden
• Portuguese: Molibdênio
• Russian:
• Spanish: Molibdeno
• Swedish: Molybden

Atomic Structure of Molybdenum

• Atomic Radius: 2.01Å
• Atomic Volume: 9.4cm³/mol
• Covalent Radius: 1.3Å
• Cross Section (Thermal Neutron Capture) _a/barns: 2.6
• Crystal Structure: Cubic body centered

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶d¹⁰ 4s²p⁶d⁵ 5s¹

• Electrons per Energy Level: 2,8,18,13,1

  Shell Model
  

• Ionic Radius: 0.65Å
• Filling Orbital: 4d⁵
• Number of Electrons (with no charge): 42
• Number of Neutrons (most common/stable nuclide): 54
• Number of Protons: 42
• Oxidation States: 6,5,4,3,2
• Valence Electrons: 4d⁵ 5s¹

  Electron Dot Model
  

Chemical Properties of Molybdenum

• Electrochemical Equivalent: 0.8949g/amp-hr
• Electron Work Function: 4.6eV
• Electronegativity: 2.16 (Pauling); 1.3 (Allrod Rochow)
• Heat of Fusion: 32kJ/mol
• Incompatibilities:

  Strong oxidizers

• Ionization Potential
  • First: 7.099
  • Second: 16.461
  • Third: 27.16
• Valence Electron Potential (-eV): 88.6

Physical Properties of Molybdenum

• Atomic Mass Average: 95.94
• Boiling Point: 4885K 4612°C 8334°F
• Coefficient of lineal thermal expansion/K^-1: 5.43E^-6
• Conductivity

  Electrical: 0.187 10⁶/cm
  Thermal: 1.38 W/cmK

• Density: 10.22g/cc @ 300K
• Description:

  Hard silvery-white transition metal.

• Elastic Modulus:
  • Bulk: 261.2/GPa
  • Rigidity: 125.6/GPa
  • Youngs: 324.8/GPa
• Enthalpy of Atomization: 653 kJ/mole @ 25°C
• Enthalpy of Fusion: 27.61 kJ/mole
• Enthalpy of Vaporization: 594.1 kJ/mole
• Flammablity Class: Combusrible Solid in powder form
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 1500 MN m^-2
  • Mohs: 5.5
  • Vickers: 1530 MN m^-2
• Heat of Vaporization: 598kJ/mol
• Melting Point: 2890K 2617°C 4743°F
  
• Molar Volume: 9.41 cm³/mole
• Optical Reflectivity: 58%
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.25J/gK
• Vapor Pressure = 3.47Pa@2617°C

Regulatory / Health

• CAS Number
  • 7439-98-7
• RTECS: QA4680000
• OSHA Permissible Exposure Limit (PEL)
  • TWA: 15 mg/m³
• OSHA PEL Vacated 1989
  • TWA: 10 mg/m³
• NIOSH Recommended Exposure Limit (REL)
  • IDLH: 5000 mg/m³
• Routes of Exposure: Inhalation; Ingestion; Skin and/or eye contact
  
• Target Organs: Eyes, respiratory system, liver, kidneys
  
• Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  • Blood/mg dm^-3: 0.001
  • Bone/p.p.m: <0.7
  • Liver/p.p.m: 1.3-5.8
  • Muscle/p.p.m: 0.018
  • Daily Dietary Intake: 0.05-0.35 mg
  • Total Mass In Avg. 70kg human: 5 mg

Who / Where / When / How

• Discoverer: Carl Wilhelm ScheeleP.J. Hjelm
• Discovery Location: Uppsala Sweden
• Discovery Year: 1781
• Name Origin:

  Greek: molubdos (lead).

• Abundance of Molybdenum:
  • Earth's Crust/p.p.m.: 1.5
  • Seawater/p.p.m.: 0.01
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 145
• Sources of Molybdenum:

  Found in the minerals molybdenite (MoS₂) and wulfenite (MoO₄Pb) also produced as a by-product of copper production. Annual world wide production is around 80,000 tons. Primary mining areas are USA, Australia, Italy, Norway, Bolivia.

• Uses of Molybdenum:

  Used in steel, aircraft, missiles, filaments in electric heaters, lubricants and protective coatings in boiler plates.

• Additional Notes:

[Last update: 2/22/2007]

Notes below

Molybdenum Menu

• Molybdenum Page One
  • Overview of Molybdenum
  • Molybdenum's Name in Other Languages
  • Atomic Structure of Molybdenum
  • Chemical Properties of Molybdenum
  • Physical Properties of Molybdenum
  • Regulatory / Health
  • Who/When/Where/How
• Molybdenum Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Molybdenum Page Three
  • Common Chemical Compounds of Molybdenum

Related Resources

• Anatomy of the Atom
  Answers many questions regarding the structure of atoms.
• Molarity, Molality and Normality
  Introduces stoichiometry and explains the differences between molarity, molality and normality.
• Molar Mass Calculations and Javascript Calculator
  Molar mass calculations are explained and there is a JavaScript calculator to aid calculations.
• Chemical Database
  This database focuses on the most common chemical compounds used in the home and industry.

Citing this page

If you need to cite this page, you can copy this text:

Kenneth Barbalace. Periodic Table of Elements - Molybdenum – Mo. EnvironmentalChemistry.com. 1995 - 2009. Accessed on-line: 1/6/2009
http://EnvironmentalChemistry.com/yogi/periodic/Mo.html
.