Properties of Promethium and Fermium
Melting Point
1,042.00 °C
  
99+
1,527.00 °C
  
26
Boiling Point
3,000.00 °C
  
31
Not Available
  
Hardness
  
  
Mohs Hardness
Not Available
  
Not Available
  
Brinell Hardness
Not Available
  
Not Available
  
Vickers Hardness
Not Available
  
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
Not Available
  
Not Available
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Pm
  
Fm
  
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+
627.00 kJ/mol
  
99+
2nd Energy Level
1,050.00 kJ/mol
  
99+
1,225.00 kJ/mol
  
99+
3rd Energy Level
2,150.00 kJ/mol
  
99+
2,363.00 kJ/mol
  
99+
Electrochemical Equivalent
1.80 g/amp-hr
  
36
3.20 g/amp-hr
  
13
Electron Work Function
Not Available
  
Not Available
  
Other Chemical Properties
Density
  
  
Density At Room Temperature
7.26 g/cm
3
  
99+
Not Available
  
Density When Liquid (at m.p.)
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Not Available
  
Vapor Pressure at 2000 K
Not Available
  
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
NA
  
Symbol
Pm
  
Fm
  
Group Number
Not Available
  
Not Available
  
Period Number
6
  
7
  
Atomic Weight
145.00 amu
  
99+
Atomic Volume
22.39 cm3/mol
  
12
Not Available
  
Electron Configuration
[Xe] 4f5 6s2
  
[Rn] 5f12 7s2
  
Valence Electron Potential
44.10 (-eV)
  
39
Not Available
  
Atom
  
  
Crystal Lattice
DHCP-Crystal-Structure-of-Promethium.jpg#100
  
Unknown-Crystal-Structure-of-Fermium.jpg#100
  
Radius of an Atom
  
  
Atomic Radius
Not Available
  
Covalent Radius
Not Available
  
Lattice Constant
Not Available
  
Not Available
  
Lattice Angles
Unknown
  
NA
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
Not Available
  
Electrical Conductivity
Not Available
  
Not Available
  
Electron Affinity
50.00 kJ/mol
  
21
Not Available
  
Electrical Property
Unknown
  
Magnetic Characteristics
  
  
Specific Gravity
Not Available
  
Magnetic Ordering
Unknown
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.18 J/(kg K)
  
33
Not Available
  
Thermal Conductivity
17.90 W/m·K
  
99+
Not Available
  
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
Not Available
  
Not Available
  
Thermal Expansion
9.00 µm/(m·K)
  
99+
Not Available
  
Standard Molar Entropy
Not Available
  
Not Available
  
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
Not Available
  
Enthalpy of Fusion
7.50 kJ/mol
  
99+
Not Available
  
Enthalpy of Atomization
310.00 kJ/mol
  
34
Not Available