Properties of Niobium and Praseodymium
Boiling Point
2,468.00 °C
  
99+
3,130.00 °C
  
27
Hardness
  
  
Mohs Hardness
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
3,480.00 m/s
  
21
2,280.00 m/s
  
40
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Nb
  
Pr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
652.10 kJ/mol
  
99+
527.00 kJ/mol
  
99+
2nd Energy Level
1,380.00 kJ/mol
  
99+
1,020.00 kJ/mol
  
99+
3rd Energy Level
2,416.00 kJ/mol
  
99+
2,086.00 kJ/mol
  
99+
Electrochemical Equivalent
0.69 g/amp-hr
  
99+
1.75 g/amp-hr
  
40
Other Chemical Properties
Density
  
  
Density At Room Temperature
8.57 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
  
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Nb
  
Pr
  
Group Number
Not Available
  
Period Number
5
  
6
  
Atomic Weight
140.91 amu
  
99+
Atomic Volume
10.87 cm3/mol
  
99+
20.80 cm3/mol
  
15
Electron Configuration
[Kr] 4d4 5s1
  
[Xe] 4f3 6s2
  
Valence Electron Potential
104.00 (-eV)
  
8
42.64 (-eV)
  
99+
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
HCP-Crystal-Structure-of-Praseodymium.jpg#100
  
Radius of an Atom
  
  
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
152.00 nΩ·m
  
23
Electrical Conductivity
0.07 106/cm Ω
  
28
0.01 106/cm Ω
  
99+
Electron Affinity
86.10 kJ/mol
  
12
50.00 kJ/mol
  
21
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.26 J/(kg K)
  
20
0.19 J/(kg K)
  
32
Thermal Conductivity
53.70 W/m·K
  
29
12.50 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
24.60 J/mol·K
  
99+
27.20 J/mol·K
  
18
Thermal Expansion
7.30 µm/(m·K)
  
99+
6.70 µm/(m·K)
  
99+
Standard Molar Entropy
36.40 J/mol.K
  
99+
73.20 J/mol.K
  
10
Enthalpy
  
  
Enthalpy of Vaporization
696.60 kJ/mol
  
4
296.80 kJ/mol
  
29
Enthalpy of Fusion
27.20 kJ/mol
  
6
6.89 kJ/mol
  
99+
Enthalpy of Atomization
745.00 kJ/mol
  
4
368.00 kJ/mol
  
24