Properties of Thorium and Hafnium
Melting Point
1,750.00 °C
  
17
2,150.00 °C
  
10
Hardness
  
  
Brinell Hardness
1,450.00 MPa
  
6
Vickers Hardness
1,520.00 MPa
  
5
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
2,490.00 m/s
  
36
3,010.00 m/s
  
27
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Th
  
Hf
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
587.00 kJ/mol
  
99+
658.50 kJ/mol
  
40
2nd Energy Level
1,110.00 kJ/mol
  
99+
1,440.00 kJ/mol
  
99+
3rd Energy Level
1,978.00 kJ/mol
  
99+
2,250.00 kJ/mol
  
99+
Electrochemical Equivalent
2.16 g/amp-hr
  
24
1.66 g/amp-hr
  
99+
Other Chemical Properties
Density
  
  
Density At Room Temperature
11.72 g/cm3
  
32
13.31 g/cm3
  
26
Density When Liquid (at m.p.)
Not Available
  
12.00 g/cm3
  
12
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Not Available
  
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Th
  
Hf
  
Period Number
7
  
6
  
Atomic Volume
19.90 cm3/mol
  
20
13.60 cm3/mol
  
38
Electron Configuration
[Rn] 6d2 7s2
  
[Xe] 4f14 5d2 6s2
  
Valence Electron Potential
59.30 (-eV)
  
23
81.00 (-eV)
  
16
Atom
  
  
Crystal Lattice
FCC-Crystal-Structure-of-Thorium.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Radius of an Atom
  
  
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
157.00 nΩ·m
  
22
331.00 nΩ·m
  
14
Electrical Conductivity
0.07 106/cm Ω
  
31
0.03 106/cm Ω
  
39
Electron Affinity
Not Available
  
0.00 kJ/mol
  
40
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.12 J/(kg K)
  
40
0.14 J/(kg K)
  
37
Thermal Conductivity
54.00 W/m·K
  
28
23.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
26.23 J/mol·K
  
30
25.73 J/mol·K
  
36
Thermal Expansion
11.00 µm/(m·K)
  
36
5.90 µm/(m·K)
  
99+
Standard Molar Entropy
27.30 J/mol.K
  
99+
43.60 J/mol.K
  
34
Enthalpy
  
  
Enthalpy of Vaporization
429.00 kJ/mol
  
15
661.10 kJ/mol
  
5
Enthalpy of Fusion
15.48 kJ/mol
  
19
25.10 kJ/mol
  
8
Enthalpy of Atomization
468.60 kJ/mol
  
15
703.00 kJ/mol
  
5