Properties of Lanthanum and Samarium
Melting Point
1,072.00 °C
  
99+
Boiling Point
3,469.00 °C
  
18
1,900.00 °C
  
99+
Hardness
  
  
Mohs Hardness
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
2,475.00 m/s
  
37
2,130.00 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
La
  
Sm
  
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
538.10 kJ/mol
  
99+
544.50 kJ/mol
  
99+
2nd Energy Level
1,067.00 kJ/mol
  
99+
1,070.00 kJ/mol
  
99+
3rd Energy Level
1,850.30 kJ/mol
  
99+
2,260.00 kJ/mol
  
99+
Electrochemical Equivalent
1.73 g/amp-hr
  
99+
1.87 g/amp-hr
  
34
Other Chemical Properties
Density
  
  
Density At Room Temperature
6.16 g/cm3
  
99+
7.52 g/cm3
  
99+
Density When Liquid (at m.p.)
5.94 g/cm3
  
99+
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
La
  
Sm
  
Group Number
Not Available
  
Not Available
  
Period Number
6
  
6
  
Atomic Weight
138.91 amu
  
99+
150.36 amu
  
99+
Atomic Volume
20.73 cm3/mol
  
16
19.95 cm3/mol
  
19
Electron Configuration
[Xe] 5d2 6s2
  
[Xe] 4f6 6s2
  
Valence Electron Potential
40.71 (-eV)
  
99+
44.80 (-eV)
  
37
Atom
  
  
Crystal Lattice
DHCP-Crystal-Structure-of-Lanthanum.jpg#100
  
RHO-Crystal-Structure-of-Samarium.jpg#100
  
Radius of an Atom
  
  
Lattice Angles
π/2, π/2, 2 π/3
  
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
48.00 kJ/mol
  
23
50.00 kJ/mol
  
21
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.19 J/(kg K)
  
32
0.20 J/(kg K)
  
31
Thermal Conductivity
13.40 W/m·K
  
99+
13.30 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
27.11 J/mol·K
  
21
29.54 J/mol·K
  
7
Thermal Expansion
12.10 µm/(m·K)
  
32
12.70 µm/(m·K)
  
30
Standard Molar Entropy
56.90 J/mol.K
  
23
69.60 J/mol.K
  
15
Enthalpy
  
  
Enthalpy of Vaporization
399.60 kJ/mol
  
17
166.40 kJ/mol
  
99+
Enthalpy of Fusion
6.20 kJ/mol
  
99+
8.62 kJ/mol
  
40
Enthalpy of Atomization
431.00 kJ/mol
  
16
209.00 kJ/mol
  
99+