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Periodic Table of Elements

Element Rhodium – Rh

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

Rhodium Menu

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

Overview of Rhodium

• Atomic Number:45
• Group: 9
• Period: 5
• Series: Transition Metals

Rhodium's Name in Other Languages

• Latin: Rhodium
• Czech: Rhodium
• Croatian: Rodij
• French: Rhodium
• German: Rhodium - s
• Italian: Rodio
• Norwegian: Rhodium
• Portuguese: Ródio
• Russian:
• Spanish: Rodio
• Swedish: Rodium

Atomic Structure of Rhodium

• Atomic Radius: 1.83Å
• Atomic Volume: 8.3cm³/mol
• Covalent Radius: 1.25Å
• Cross Section (Thermal Neutron Capture) _a/barns: 144.8
• Crystal Structure: Cubic face centered

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶d¹⁰ 4s²p⁶d⁸ 5s¹

• Electrons per Energy Level: 2,8,18,16,1

  Shell Model
  

• Ionic Radius: 0.68Å
• Filling Orbital: 4d⁸
• Number of Electrons (with no charge): 45
• Number of Neutrons (most common/stable nuclide): 58
• Number of Protons: 45
• Oxidation States: 2,3,4
• Valence Electrons: 4d⁸ 5s¹

Chemical Properties of Rhodium

• Electrochemical Equivalent: 1.2798g/amp-hr
• Electron Work Function: 4.98eV
• Electronegativity: 2.28 (Pauling); 1.45 (Allrod Rochow)
• Heat of Fusion: 21.5kJ/mol
• Incompatibilities:

  Chlorine trifluoride, oxygen difluoride

• Ionization Potential
  • First: 7.46
  • Second: 18.08
  • Third: 31.06
• Valence Electron Potential (-eV): 64

Physical Properties of Rhodium

• Atomic Mass Average: 102.9055
• Boiling Point: 4000K 3727°C 6741°F
• Coefficient of lineal thermal expansion/K^-1: 8.4E^-6
• Conductivity

  Electrical: 0.211 10⁶/cm
  Thermal: 1.5 W/cmK

• Density: 12.41g/cc @ 300K
• Description:

  Hard silver white metal that is unaffected by air and water up to 875K. It is also unaffected by acids but is attacked by multen alkalis.

• Elastic Modulus:
  • Bulk: 276/GPa
  • Rigidity: 147/GPa
  • Youngs: 379/GPa
• Enthalpy of Atomization: 556.5 kJ/mole @ 25°C
• Enthalpy of Fusion: 21.76 kJ/mole
• Enthalpy of Vaporization: 495.4 kJ/mole
• Flammablity Class: Non-combustible solid (except as dust)
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 1100 MN m^-2
  • Mohs: 6
  • Vickers: 1246 MN m^-2
• Heat of Vaporization: 493kJ/mol
• Melting Point: 2239K 1966°C 3571°F
  
• Molar Volume: 8.3 cm³/mole
• Optical Reflectivity: 84%
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.242J/gK
• Vapor Pressure = 0.633Pa@1966°C

Regulatory / Health

• CAS Number
  • 7440-16-6
• RTECS: VI9069000
• OSHA Permissible Exposure Limit (PEL)
  • TWA: 0.1 mg/m³
• OSHA PEL Vacated 1989
  • TWA: 0.1 mg/m³
• NIOSH Recommended Exposure Limit (REL)
  • TWA: 0.1 mg/m³
  • IDLH: 100 mg/m³
• Routes of Exposure: Inhalation
  
• Target Organs: Respiratory system
  
• 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: William H. Wollaston
• Discovery Location: London England
• Discovery Year: 1803
• Name Origin:

  Greek: rhodon (rose). Its salts give a rosy solution.

• Abundance of Rhodium:
  • Earth's Crust/p.p.m.: 0.0002
  • Seawater/p.p.m.: N/A
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 25.1
• Sources of Rhodium:

  Obtained as a by-product of nickel production. Rhodium is found in its native state in Montana USA. Around three tons of Rhodium are produced world wide on an annual basis.

• Uses of Rhodium:

  Used as a coating to prevent wear on high quality science equipment and with platinum to make thermocouples. Also used in headlight reflectors, thelephone relays, fountain pen points and airplane spark plugs.

• Additional Notes:

[Last update: 2/22/2007]

Notes below

Rhodium Menu

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

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 - Rhodium – Rh. EnvironmentalChemistry.com. 1995 - 2009. Accessed on-line: 1/7/2009
http://EnvironmentalChemistry.com/yogi/periodic/Rh.html
.