Properties of Radium and Iridium
Boiling Point
1,737.00 °C
  
99+
4,527.00 °C
  
10
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
1,670.00 MPa
  
5
Vickers Hardness
Not Available
  
1,760.00 MPa
  
3
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Speed of Sound
Not Available
  
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
Ra
  
Ir
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
509.30 kJ/mol
  
99+
880.00 kJ/mol
  
9
2nd Energy Level
979.00 kJ/mol
  
99+
1,600.00 kJ/mol
  
35
3rd Energy Level
Not Available
  
Not Available
  
Electrochemical Equivalent
4.22 g/amp-hr
  
6
1.14 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Density
  
  
Density At Room Temperature
5.50 g/cm3
  
99+
22.56 g/cm3
  
10
Density When Liquid (at m.p.)
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Not Available
  
Vapor Pressure at 2000 K
Not Available
  
Tensile Strength
Not Available
  
2,000.00 MPa
  
2
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
NA
  
Symbol
Ra
  
Ir
  
Period Number
7
  
6
  
Atomic Volume
45.20 cm3/mol
  
4
9.53 cm3/mol
  
99+
Electron Configuration
[Rn] 7s2
  
[Xe] 4f14 5d7 6s2
  
Valence Electron Potential
20.10 (-eV)
  
99+
140.00 (-eV)
  
5
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
FCC-Crystal-Structure-of-Iridium.jpg#100
  
Radius of an Atom
  
  
Atomic Radius
Not Available
  
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
100.00 nΩ·m
  
31
47.10 nΩ·m
  
99+
Electrical Conductivity
Not Available
  
0.19 10
6/cm Ω
  
10
Electron Affinity
Not Available
  
151.00 kJ/mol
  
4
Electrical Property
NA
  
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.12 J/(kg K)
  
40
0.13 J/(kg K)
  
39
Thermal Conductivity
18.60 W/m·K
  
99+
147.00 W/m·K
  
10
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
Not Available
  
25.10 J/mol·K
  
99+
Thermal Expansion
Not Available
  
6.40 µm/(m·K)
  
99+
Standard Molar Entropy
71.00 J/mol.K
  
14
35.50 J/mol.K
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
799.10 kJ/mol
  
1
Enthalpy of Fusion
Not Available
  
35.23 kJ/mol
  
1
Enthalpy of Atomization
163.00 kJ/mol
  
99+
837.00 kJ/mol
  
1