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Periodic Table of Elements

Element Iridium - Ir

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

Iridium Menu

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

Overview of Iridium

• Atomic Number: 77
• Group: 9
• Period: 6
• Series: Transition Metals

Iridium's Name in Other Languages

• Latin: Iridium
• Czech: Iridium
• Croatian: Iridij
• French: Iridium
• German: Iridium - s
• Italian: Iridio
• Norwegian: Irdium
• Portuguese: Irídio
• Russian: Иридий
• Spanish: Iridio
• Swedish: Iridium

Atomic Structure of Iridium

• Atomic Radius: 1.87Å
• Atomic Volume: 8.54cm³/mol
• Covalent Radius: 1.27Å
• Cross Section (Thermal Neutron Capture) σ_a/barns: 425
• Crystal Structure: Cubic face centered

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶d¹⁰ 4s²p⁶d¹⁰f¹⁴ 5s²p⁶d⁷ 6s²

• Electrons per Energy Level: 2,8,18,32,15,2

  Shell Model
  

• Ionic Radius: 0.625Å
• Filling Orbital: 5d⁷
• Number of Electrons (with no charge): 77
• Number of Neutrons (most common/stable nuclide): 115
• Number of Protons: 77
• Oxidation States: 2,3,4,6
• Valence Electrons: 5d⁷ 6s²

Chemical Properties of Iridium

• Electrochemical Equivalent: 1.793g/amp-hr
• Electron Work Function: 5.27eV
• Electronegativity: 2.2 (Pauling); 1.55 (Allrod Rochow)
• Heat of Fusion: 26.1kJ/mol
• Incompatibilities:

• Ionization Potential
  • First: 9.1
• Valence Electron Potential (-eV): 92.2

Physical Properties of Iridium

• Atomic Mass Average: 192.22
• Boiling Point: 4701K 4428°C 8002°F
• Coefficient of lineal thermal expansion/K^-1: 6.4E^-6
• Conductivity

  Electrical: 0.197 10⁶/cm Ω
  Thermal: 1.47 W/cmK

• Density: 22.4g/cc @ 300K
• Description:

  Heavy brittle white transition metal.

• Elastic Modulus:
  • Bulk: 371/GPa
  • Rigidity: 209/GPa
  • Youngs: 528/GPa
• Enthalpy of Atomization: 628 kJ/mole @ 25°C
• Enthalpy of Fusion: 26.4 kJ/mole
• Enthalpy of Vaporization: 563.6 kJ/mole
• Flammablity Class:
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 1670 MN m^-2
  • Mohs: 6.5
  • Vickers: 1760 MN m^-2
• Heat of Vaporization: 604kJ/mol
• Melting Point: 2716K 2443°C 4429°F
• Molar Volume: 8.49 cm³/mole
• Optical Reflectivity: 78%
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.13J/gK
• Vapor Pressure = 1.47Pa@2443°C

Regulatory / Health

• CAS Number
  • 7439-88-5
• RTECS: 1002594IR
• OSHA Permissible Exposure Limit (PEL)
  • No limits set by OSHA
• OSHA PEL Vacated 1989
  • No limits set by OSHA
• NIOSH Recommended Exposure Limit (REL)
  • No limits set by NIOSH
• 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: 2E-5
  • Daily Dietary Intake: n/a
  • Total Mass In Avg. 70kg human: n/a

Who / Where / When / How

• Discoverer: S.Tennant
• Discovery Location: London England
• Discovery Year: 1803
• Name Origin:

  Latin: iris, iridis (rainbow).

• Abundance of Iridium:
  • Earth's Crust/p.p.m.: 0.000003
  • Seawater/p.p.m.: N/A
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 7.1
• Sources of Iridium:

  Found in gravel deposits with platinum and osmiridium ores. Annual world production is around 3 tons. Canada is the primary mining area for iridium.

• Uses of Iridium:

  Used with osmium to tip gold pen points, to make crucible and special containers. Used to make alloys used for standard weights and measures, and heat-resistant alloys. Also used incancer irradiation, hypodermic needles, helicopter spark plugs and as hardening agent for platinum.

• Additional Notes:

Iridium Menu

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

References

A list of reference sources used to compile the data provided on our periodic table of elements can be found on the main periodic table page.

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• Chemical Database
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Citing this page

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Kenneth Barbalace. Periodic Table of Elements - Iridium - Ir. EnvironmentalChemistry.com. 1995 - 2024. Accessed on-line: 12/21/2024
https://EnvironmentalChemistry.com/yogi/periodic/Ir.html
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