Properties of Europium and Terbium
Melting Point
1,356.00 °C
  
33
Boiling Point
1,597.00 °C
  
99+
3,123.00 °C
  
29
Hardness
  
  
Mohs Hardness
Not Available
  
Not Available
  
Brinell Hardness
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
Not Available
  
2,620.00 m/s
  
35
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Eu
  
Tb
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Not Available
  
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Not Available
  
Mulliken-Jaffe Electronegativity
Not Available
  
Not Available
  
Allen Electronegativity
Not Available
  
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Not Available
  
Not Available
  
Ionization Energies
  
  
1st Energy Level
547.10 kJ/mol
  
99+
603.40 kJ/mol
  
99+
2nd Energy Level
1,085.00 kJ/mol
  
99+
1,174.80 kJ/mol
  
99+
3rd Energy Level
2,404.00 kJ/mol
  
99+
2,417.00 kJ/mol
  
99+
Electrochemical Equivalent
1.89 g/amp-hr
  
33
1.98 g/amp-hr
  
31
Other Chemical Properties
Density
  
  
Density At Room Temperature
5.26 g/cm3
  
99+
8.23 g/cm3
  
99+
Density When Liquid (at m.p.)
5.13 g/cm3
  
99+
Vapor Pressure
  
  
Vapor Pressure at 2000 K
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Eu
  
Tb
  
Group Number
Not Available
  
Not Available
  
Period Number
6
  
6
  
Atomic Weight
151.96 amu
  
99+
158.93 amu
  
99+
Atomic Volume
28.90 cm3/mol
  
8
19.20 cm3/mol
  
22
Electron Configuration
[Xe] 4f7 6s2
  
[Xe] 4f9 6s2
  
Valence Electron Potential
45.60 (-eV)
  
35
46.80 (-eV)
  
33
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
HCP-Crystal-Structure-of-Terbium.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
  
  
Electrical Conductivity
0.01 106/cm Ω
  
99+
0.01 106/cm Ω
  
99+
Electron Affinity
50.00 kJ/mol
  
21
50.00 kJ/mol
  
21
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.18 J/(kg K)
  
33
0.18 J/(kg K)
  
33
Thermal Conductivity
13.90 W/m·K
  
99+
11.10 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
27.66 J/mol·K
  
16
28.91 J/mol·K
  
9
Thermal Expansion
35.00 µm/(m·K)
  
8
10.30 µm/(m·K)
  
38
Standard Molar Entropy
77.80 J/mol.K
  
4
73.20 J/mol.K
  
10
Enthalpy
  
  
Enthalpy of Vaporization
143.50 kJ/mol
  
99+
330.90 kJ/mol
  
26
Enthalpy of Fusion
9.21 kJ/mol
  
37
10.80 kJ/mol
  
34
Enthalpy of Atomization
180.00 kJ/mol
  
99+
314.00 kJ/mol
  
33