Properties of Thorium and Zirconium
Melting Point
1,750.00 °C
  
17
1,852.00 °C
  
15
Boiling Point
4,377.00 °C
  
11
Hardness
  
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
2,490.00 m/s
  
36
3,800.00 m/s
  
20
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Th
  
Zr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
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+
640.10 kJ/mol
  
99+
2nd Energy Level
1,110.00 kJ/mol
  
99+
1,270.00 kJ/mol
  
99+
3rd Energy Level
1,978.00 kJ/mol
  
99+
2,218.00 kJ/mol
  
99+
Electrochemical Equivalent
2.16 g/amp-hr
  
24
0.85 g/amp-hr
  
99+
Other Chemical Properties
Density
  
  
Density At Room Temperature
11.72 g/cm3
  
32
6.52 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
5.80 g/cm3
  
99+
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
  
Zr
  
Period Number
7
  
5
  
Atomic Volume
19.90 cm3/mol
  
20
14.10 cm3/mol
  
36
Electron Configuration
[Rn] 6d2 7s2
  
[Kr] 4d2 5s2
  
Valence Electron Potential
59.30 (-eV)
  
23
80.00 (-eV)
  
18
Atom
  
  
Crystal Lattice
FCC-Crystal-Structure-of-Thorium.jpg#100
  
HCP-Crystal-Structure-of-Zirconium.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
421.00 nΩ·m
  
11
Electrical Conductivity
0.07 106/cm Ω
  
31
0.02 106/cm Ω
  
99+
Electron Affinity
Not Available
  
41.10 kJ/mol
  
27
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.12 J/(kg K)
  
40
0.27 J/(kg K)
  
19
Thermal Conductivity
54.00 W/m·K
  
28
22.60 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
26.23 J/mol·K
  
30
25.36 J/mol·K
  
99+
Thermal Expansion
11.00 µm/(m·K)
  
36
5.70 µm/(m·K)
  
99+
Standard Molar Entropy
27.30 J/mol.K
  
99+
39.00 J/mol.K
  
39
Enthalpy
  
  
Enthalpy of Vaporization
429.00 kJ/mol
  
15
581.60 kJ/mol
  
9
Enthalpy of Fusion
15.48 kJ/mol
  
19
20.90 kJ/mol
  
11
Enthalpy of Atomization
468.60 kJ/mol
  
15
598.00 kJ/mol
  
10