Properties of Rhenium and Niobium
Boiling Point
2,468.00 °C
  
99+
Hardness
  
  
Brinell Hardness
1,320.00 MPa
  
8
Vickers Hardness
1,350.00 MPa
  
7
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
4,700.00 m/s
  
15
3,480.00 m/s
  
21
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Re
  
Nb
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
760.00 kJ/mol
  
20
652.10 kJ/mol
  
99+
2nd Energy Level
1,260.00 kJ/mol
  
99+
1,380.00 kJ/mol
  
99+
3rd Energy Level
2,510.00 kJ/mol
  
99+
2,416.00 kJ/mol
  
99+
Electrochemical Equivalent
0.99 g/amp-hr
  
99+
0.69 g/amp-hr
  
99+
Other Chemical Properties
Density
  
  
Density At Room Temperature
21.02 g/cm3
  
12
8.57 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Not Available
  
Tensile Strength
1,070.00 MPa
  
3
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Symbol
Re
  
Nb
  
Period Number
6
  
5
  
Atomic Volume
8.85 cm3/mol
  
99+
10.87 cm3/mol
  
99+
Electron Configuration
[Xe] 4f14 5d5 6s2
  
[Kr] 4d4 5s1
  
Valence Electron Potential
180.00 (-eV)
  
3
104.00 (-eV)
  
8
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Radius of an Atom
  
  
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
193.00 nΩ·m
  
20
152.00 nΩ·m
  
23
Electrical Conductivity
0.05 106/cm Ω
  
33
0.07 106/cm Ω
  
28
Electron Affinity
14.50 kJ/mol
  
35
86.10 kJ/mol
  
12
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.13 J/(kg K)
  
39
0.26 J/(kg K)
  
20
Thermal Conductivity
48.00 W/m·K
  
31
53.70 W/m·K
  
29
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
25.48 J/mol·K
  
38
24.60 J/mol·K
  
99+
Thermal Expansion
6.20 µm/(m·K)
  
99+
7.30 µm/(m·K)
  
99+
Standard Molar Entropy
36.90 J/mol.K
  
99+
36.40 J/mol.K
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
707.10 kJ/mol
  
3
696.60 kJ/mol
  
4
Enthalpy of Fusion
33.05 kJ/mol
  
2
27.20 kJ/mol
  
6
Enthalpy of Atomization
791.00 kJ/mol
  
2
745.00 kJ/mol
  
4