Properties of Tantalum and Thorium
Melting Point
1,750.00 °C
  
17
Hardness
  
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Speed of Sound
3,400.00 m/s
  
22
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
Ta
  
Th
  
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
761.00 kJ/mol
  
18
587.00 kJ/mol
  
99+
2nd Energy Level
1,500.00 kJ/mol
  
40
1,110.00 kJ/mol
  
99+
3rd Energy Level
Not Available
  
1,978.00 kJ/mol
  
99+
Electrochemical Equivalent
1.35 g/amp-hr
  
99+
2.16 g/amp-hr
  
24
Other Chemical Properties
Density
  
  
Density At Room Temperature
16.69 g/cm3
  
18
11.72 g/cm3
  
32
Density When Liquid (at m.p.)
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Ta
  
Th
  
Period Number
6
  
7
  
Atomic Volume
10.90 cm3/mol
  
99+
19.90 cm3/mol
  
20
Electron Configuration
[Xe] 4f14 5d3 6s2
  
[Rn] 6d2 7s2
  
Valence Electron Potential
110.00 (-eV)
  
7
59.30 (-eV)
  
23
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
FCC-Crystal-Structure-of-Thorium.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
131.00 nΩ·m
  
25
157.00 nΩ·m
  
22
Electrical Conductivity
0.08 106/cm Ω
  
27
0.07 106/cm Ω
  
31
Electron Affinity
31.00 kJ/mol
  
29
Not Available
  
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.14 J/(kg K)
  
37
0.12 J/(kg K)
  
40
Thermal Conductivity
57.50 W/m·K
  
27
54.00 W/m·K
  
28
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
25.36 J/mol·K
  
99+
26.23 J/mol·K
  
30
Thermal Expansion
6.30 µm/(m·K)
  
99+
11.00 µm/(m·K)
  
36
Standard Molar Entropy
41.50 J/mol.K
  
37
27.30 J/mol.K
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
753.10 kJ/mol
  
2
429.00 kJ/mol
  
15
Enthalpy of Fusion
31.40 kJ/mol
  
3
15.48 kJ/mol
  
19
Enthalpy of Atomization
782.00 kJ/mol
  
3
468.60 kJ/mol
  
15