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Periodic Table of Elements

Element Hafnium - Hf

Comprehensive data on the chemical element Hafnium is provided on this page; including scores of properties, element names in many languages, most known nuclides of Hafnium. 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.

Hafnium Menu

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

Overview of Hafnium

• Atomic Number:72
• Group: 4
• Period: 6
• Series: Transition Metals

Hafnium's Name in Other Languages

• Latin: Hafnium
• Czech: Hafnium
• Croatian: Hafnij
• French: Hafnium
• German: Hafnium - s
• Italian: Afnio
• Norwegian: Hafnium
• Portuguese: Háfnio
• Russian:
• Spanish: Hafnio
• Swedish: Hafnium

Atomic Structure of Hafnium

• Atomic Radius: 2.16Å
• Atomic Volume: 13.6cm³/mol
• Covalent Radius: 1.44Å
• Cross Section (Thermal Neutron Capture) σ_a/barns: 104
• Crystal Structure: Hexagonal

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶d¹⁰ 4s²p⁶d¹⁰f¹⁴ 5s²p⁶d² 6s²

• Electrons per Energy Level: 2,8,18,32,10,2

  Shell Model
  

• Ionic Radius: 0.71Å
• Filling Orbital: 5d²
• Number of Electrons (with no charge): 72
• Number of Neutrons (most common/stable nuclide): 106
• Number of Protons: 72
• Oxidation States: 4
• Valence Electrons: 5d⁶ 6s²

  Electron Dot Model
  

Chemical Properties of Hafnium

• Electrochemical Equivalent: 1.6649g/amp-hr
• Electron Work Function: 3.9eV
• Electronegativity: 1.3 (Pauling); 1.23 (Allrod Rochow)
• Heat of Fusion: 24.06kJ/mol
• Incompatibilities:

  Strong oxidizers, chlorine

• Ionization Potential
  • First: 6.65
  • Second: 14.925
  • Third: 23.32
• Valence Electron Potential (-eV): 81

Physical Properties of Hafnium

• Atomic Mass Average: 178.49
• Boiling Point: 4876K 4603°C 8317°F
• Coefficient of lineal thermal expansion/K^-1: 5.9E^-6
• Conductivity

  Electrical: 0.0312 10⁶/cm Ω
  Thermal: 0.23 W/cmK

• Density: 13.31g/cc @ 300K
• Description:

  Silver colored ductile transition metal that resists corrosion.

• Elastic Modulus:
  • Bulk: 109/GPa
  • Rigidity: 56/GPa
  • Youngs: 141/GPa
• Enthalpy of Atomization: 703 kJ/mole @ 25°C
• Enthalpy of Fusion: 25.1 kJ/mole
• Enthalpy of Vaporization: 661.1 kJ/mole
• Flammablity Class: Explosive in powder form
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 1700 MN m^-2
  • Mohs: 5.5
  • Vickers: 1760 MN m^-2
• Heat of Vaporization: 575kJ/mol
• Melting Point: 2500K 2227°C 4041°F
  
• Molar Volume: 13.41 cm³/mole
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.14J/gK
• Vapor Pressure = 0.00112Pa@2227°C

Regulatory / Health

• CAS Number
  • 7440-58-6 powder, wet
• UN/NA ID and ERG Guide Number
  • 1326  / 170 powder, wet
  • 2545  / 135 powder, dry
• RTECS: MG4600000
• OSHA Permissible Exposure Limit (PEL)
  • TWA: 0.5 mg/m³
• OSHA PEL Vacated 1989
  • TWA: 0.5 mg/m³
• NIOSH Recommended Exposure Limit (REL)
  • TWA: 0.5 mg/m³
  • IDLH: 50 mg/m³
• Routes of Exposure: Inhalation; Ingestion; Skin and/or eye contact
  
• Target Organs: Eyes, skin, mucous membrane , liver
  
• 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: n/a
  • Bone/p.p.m: n/a
  • Liver/p.p.m: n/a
  • Muscle/p.p.m: n/a
  • Daily Dietary Intake: n/a
  • Total Mass In Avg. 70kg human: n/a

Who / Where / When / How

• Discoverer: Dirk Coster, Georg C. von Hevesy
• Discovery Location: Copenhagen Denmark
• Discovery Year: 1923
• Name Origin:

  From Hafnia Latin name of Copenhagen.

• Abundance of Hafnium:
  • Earth's Crust/p.p.m.: 5.3
  • Seawater/p.p.m.: 0.000007
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 6
• Sources of Hafnium:

  Obtained as a by-product zirconium refining. Around 50 tons are produced world wide annually.

• Uses of Hafnium:

  Used in reactor control rods because of its ability to absorb neutrons also as a gas scavenger in vacuum tubes.

• Additional Notes:

  Hafnium is poorly absorbed by the body. As a result poisoning by compounds of hafnium is rare.

[Last update: 2/22/2007]

Hafnium Menu

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

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Citing this page

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

Kenneth Barbalace. Periodic Table of Elements - Hafnium - Hf. EnvironmentalChemistry.com. 1995 - 2009. Accessed on-line: 12/28/2009
http://EnvironmentalChemistry.com/yogi/periodic/Hf.html
.