Properties of Promethium and Cerium
Melting Point
1,042.00 °C
  
99+
Boiling Point
3,000.00 °C
  
31
3,257.00 °C
  
23
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
186.00 MPa
  
99+
Vickers Hardness
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
Not Available
  
2,100.00 m/s
  
99+
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Pm
  
Ce
  
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
540.00 kJ/mol
  
99+
534.40 kJ/mol
  
99+
2nd Energy Level
1,050.00 kJ/mol
  
99+
1,050.00 kJ/mol
  
99+
3rd Energy Level
2,150.00 kJ/mol
  
99+
1,949.00 kJ/mol
  
99+
Electrochemical Equivalent
1.80 g/amp-hr
  
36
1.74 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Density
  
  
Density At Room Temperature
7.26 g/cm3
  
99+
6.77 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Vapor Pressure at 2000 K
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
NA
  
Symbol
Pm
  
Ce
  
Group Number
Not Available
  
Not Available
  
Period Number
6
  
6
  
Atomic Weight
145.00 amu
  
99+
140.12 amu
  
99+
Atomic Volume
22.39 cm3/mol
  
12
20.67 cm3/mol
  
17
Electron Configuration
[Xe] 4f5 6s2
  
[Xe] 4f1 5d1 6s2
  
Valence Electron Potential
44.10 (-eV)
  
39
41.78 (-eV)
  
99+
Atom
  
  
Crystal Lattice
DHCP-Crystal-Structure-of-Promethium.jpg#100
  
DHCP-Crystal-Structure-of-Cerium.jpg#100
  
Radius of an Atom
  
  
Lattice Constant
Not Available
  
Lattice Angles
Unknown
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Electrical Conductivity
Not Available
  
0.01 10
6/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
0.19 J/(kg K)
  
32
Thermal Conductivity
17.90 W/m·K
  
99+
11.30 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
Not Available
  
26.94 J/mol·K
  
23
Thermal Expansion
9.00 µm/(m·K)
  
99+
6.30 µm/(m·K)
  
99+
Standard Molar Entropy
Not Available
  
72.00 J/mol.K
  
12
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
414.00 kJ/mol
  
16
Enthalpy of Fusion
7.50 kJ/mol
  
99+
5.46 kJ/mol
  
99+
Enthalpy of Atomization
310.00 kJ/mol
  
34
381.00 kJ/mol
  
23