Properties of Rhodium and Iridium
Melting Point
1,966.00 °C
  
12
Boiling Point
3,727.00 °C
  
17
4,527.00 °C
  
10
Hardness
  
  
Brinell Hardness
1,670.00 MPa
  
5
Vickers Hardness
1,100.00 MPa
  
9
1,760.00 MPa
  
3
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Speed of Sound
4,700.00 m/s
  
15
4,825.00 m/s
  
13
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Rh
  
Ir
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
719.70 kJ/mol
  
29
880.00 kJ/mol
  
9
2nd Energy Level
1,740.00 kJ/mol
  
26
1,600.00 kJ/mol
  
35
3rd Energy Level
2,997.00 kJ/mol
  
27
Not Available
  
Electrochemical Equivalent
1.28 g/amp-hr
  
99+
1.14 g/amp-hr
  
99+
Other Chemical Properties
Density
  
  
Density At Room Temperature
12.41 g/cm3
  
28
22.56 g/cm3
  
10
Density When Liquid (at m.p.)
10.70 g/cm3
  
14
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Not Available
  
Tensile Strength
2,000.00 MPa
  
2
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
NA
  
Symbol
Rh
  
Ir
  
Period Number
5
  
6
  
Atomic Weight
102.91 amu
  
99+
Atomic Volume
8.30 cm3/mol
  
99+
9.53 cm3/mol
  
99+
Electron Configuration
[Kr] 4d8 5s1
  
[Xe] 4f14 5d7 6s2
  
Valence Electron Potential
64.00 (-eV)
  
22
140.00 (-eV)
  
5
Atom
  
  
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
  
FCC-Crystal-Structure-of-Iridium.jpg#100
  
Radius of an Atom
  
  
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
43.30 nΩ·m
  
99+
47.10 nΩ·m
  
99+
Electrical Conductivity
0.21 106/cm Ω
  
8
0.19 106/cm Ω
  
10
Electron Affinity
109.70 kJ/mol
  
7
151.00 kJ/mol
  
4
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.24 J/(kg K)
  
22
0.13 J/(kg K)
  
39
Thermal Conductivity
150.00 W/m·K
  
9
147.00 W/m·K
  
10
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
24.98 J/mol·K
  
99+
25.10 J/mol·K
  
99+
Thermal Expansion
8.20 µm/(m·K)
  
99+
6.40 µm/(m·K)
  
99+
Standard Molar Entropy
31.50 J/mol.K
  
99+
35.50 J/mol.K
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
495.40 kJ/mol
  
12
799.10 kJ/mol
  
1
Enthalpy of Fusion
21.76 kJ/mol
  
10
35.23 kJ/mol
  
1
Enthalpy of Atomization
556.50 kJ/mol
  
12
837.00 kJ/mol
  
1