Properties of Praseodymium and Lanthanum
Boiling Point
3,130.00 °C
  
27
3,469.00 °C
  
18
Hardness
  
  
Mohs Hardness
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
2,280.00 m/s
  
40
2,475.00 m/s
  
37
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Pr
  
La
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
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
Ionization Energies
  
  
1st Energy Level
527.00 kJ/mol
  
99+
538.10 kJ/mol
  
99+
2nd Energy Level
1,020.00 kJ/mol
  
99+
1,067.00 kJ/mol
  
99+
3rd Energy Level
2,086.00 kJ/mol
  
99+
1,850.30 kJ/mol
  
99+
Electrochemical Equivalent
1.75 g/amp-hr
  
40
1.73 g/amp-hr
  
99+
Other Chemical Properties
Density
  
  
Density At Room Temperature
6.77 g/cm3
  
99+
6.16 g/cm3
  
99+
Density When Liquid (at m.p.)
5.94 g/cm3
  
99+
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Pr
  
La
  
Group Number
Not Available
  
Not Available
  
Period Number
6
  
6
  
Atomic Weight
140.91 amu
  
99+
138.91 amu
  
99+
Atomic Volume
20.80 cm3/mol
  
15
20.73 cm3/mol
  
16
Electron Configuration
[Xe] 4f3 6s2
  
[Xe] 5d2 6s2
  
Valence Electron Potential
42.64 (-eV)
  
99+
40.71 (-eV)
  
99+
Atom
  
  
Crystal Lattice
HCP-Crystal-Structure-of-Praseodymium.jpg#100
  
DHCP-Crystal-Structure-of-Lanthanum.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
48.00 kJ/mol
  
23
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.19 J/(kg K)
  
32
0.19 J/(kg K)
  
32
Thermal Conductivity
12.50 W/m·K
  
99+
13.40 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
27.20 J/mol·K
  
18
27.11 J/mol·K
  
21
Thermal Expansion
6.70 µm/(m·K)
  
99+
12.10 µm/(m·K)
  
32
Standard Molar Entropy
73.20 J/mol.K
  
10
56.90 J/mol.K
  
23
Enthalpy
  
  
Enthalpy of Vaporization
296.80 kJ/mol
  
29
399.60 kJ/mol
  
17
Enthalpy of Fusion
6.89 kJ/mol
  
99+
6.20 kJ/mol
  
99+
Enthalpy of Atomization
368.00 kJ/mol
  
24
431.00 kJ/mol
  
16