Properties of Gadolinium and Terbium
Melting Point
1,311.00 °C
  
35
1,356.00 °C
  
33
Boiling Point
3,233.00 °C
  
25
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
2,680.00 m/s
  
34
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
Gd
  
Tb
  
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
593.40 kJ/mol
  
99+
603.40 kJ/mol
  
99+
2nd Energy Level
1,170.00 kJ/mol
  
99+
1,174.80 kJ/mol
  
99+
3rd Energy Level
1,990.00 kJ/mol
  
99+
2,417.00 kJ/mol
  
99+
Electrochemical Equivalent
1.96 g/amp-hr
  
32
1.98 g/amp-hr
  
31
Other Chemical Properties
Density
  
  
Density At Room Temperature
7.90 g/cm3
  
99+
8.23 g/cm3
  
99+
Density When Liquid (at m.p.)
Vapor Pressure
  
  
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Gd
  
Tb
  
Group Number
Not Available
  
Period Number
6
  
6
  
Atomic Weight
158.93 amu
  
99+
Atomic Volume
19.90 cm3/mol
  
20
19.20 cm3/mol
  
22
Electron Configuration
[Xe] 4f7 5d1 6s2
  
[Xe] 4f9 6s2
  
Valence Electron Potential
46.10 (-eV)
  
34
46.80 (-eV)
  
33
Atom
  
  
Crystal Lattice
HCP-Crystal-Structure-of-Gadolinium.jpg#100
  
HCP-Crystal-Structure-of-Terbium.jpg#100
  
Radius of an Atom
  
  
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, 2 π/3
  
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
  
  
Magnetic Ordering
Ferromagnetic
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.23 J/(kg K)
  
27
0.18 J/(kg K)
  
33
Thermal Conductivity
10.60 W/m·K
  
99+
11.10 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
37.03 J/mol·K
  
2
28.91 J/mol·K
  
9
Thermal Expansion
9.40 µm/(m·K)
  
99+
10.30 µm/(m·K)
  
38
Standard Molar Entropy
68.10 J/mol.K
  
16
73.20 J/mol.K
  
10
Enthalpy
  
  
Enthalpy of Vaporization
359.40 kJ/mol
  
21
330.90 kJ/mol
  
26
Enthalpy of Fusion
10.05 kJ/mol
  
36
10.80 kJ/mol
  
34
Enthalpy of Atomization
352.00 kJ/mol
  
27
314.00 kJ/mol
  
33