Properties of Terbium and Thorium
Melting Point
1,356.00 °C
  
33
1,750.00 °C
  
17
Boiling Point
3,123.00 °C
  
29
Hardness
  
  
Mohs Hardness
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
2,620.00 m/s
  
35
2,490.00 m/s
  
36
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Tb
  
Th
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Not Available
  
Sanderson Electronegativity
Not Available
  
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Not Available
  
Allen Electronegativity
Not Available
  
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Not Available
  
Ionization Energies
  
  
1st Energy Level
603.40 kJ/mol
  
99+
587.00 kJ/mol
  
99+
2nd Energy Level
1,174.80 kJ/mol
  
99+
1,110.00 kJ/mol
  
99+
3rd Energy Level
2,417.00 kJ/mol
  
99+
1,978.00 kJ/mol
  
99+
Electrochemical Equivalent
1.98 g/amp-hr
  
31
2.16 g/amp-hr
  
24
Other Chemical Properties
Density
  
  
Density At Room Temperature
8.23 g/cm3
  
99+
11.72 g/cm3
  
32
Density When Liquid (at m.p.)
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Tb
  
Th
  
Group Number
Not Available
  
Period Number
6
  
7
  
Atomic Weight
158.93 amu
  
99+
Atomic Volume
19.20 cm3/mol
  
22
19.90 cm3/mol
  
20
Electron Configuration
[Xe] 4f9 6s2
  
[Rn] 6d2 7s2
  
Valence Electron Potential
46.80 (-eV)
  
33
59.30 (-eV)
  
23
Atom
  
  
Crystal Lattice
HCP-Crystal-Structure-of-Terbium.jpg#100
  
FCC-Crystal-Structure-of-Thorium.jpg#100
  
Radius of an Atom
  
  
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
157.00 nΩ·m
  
22
Electrical Conductivity
0.01 106/cm Ω
  
99+
0.07 106/cm Ω
  
31
Electron Affinity
50.00 kJ/mol
  
21
Not Available
  
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.18 J/(kg K)
  
33
0.12 J/(kg K)
  
40
Thermal Conductivity
11.10 W/m·K
  
99+
54.00 W/m·K
  
28
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
28.91 J/mol·K
  
9
26.23 J/mol·K
  
30
Thermal Expansion
10.30 µm/(m·K)
  
38
11.00 µm/(m·K)
  
36
Standard Molar Entropy
73.20 J/mol.K
  
10
27.30 J/mol.K
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
330.90 kJ/mol
  
26
429.00 kJ/mol
  
15
Enthalpy of Fusion
10.80 kJ/mol
  
34
15.48 kJ/mol
  
19
Enthalpy of Atomization
314.00 kJ/mol
  
33
468.60 kJ/mol
  
15