Properties of Francium and Niobium
Boiling Point
2,468.00 °C
  
99+
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
Vickers Hardness
Not Available
  
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
Not Available
  
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
Fr
  
Nb
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
380.00 kJ/mol
  
99+
652.10 kJ/mol
  
99+
2nd Energy Level
Not Available
  
1,380.00 kJ/mol
  
99+
3rd Energy Level
Not Available
  
2,416.00 kJ/mol
  
99+
Electrochemical Equivalent
8.32 g/amp-hr
  
1
0.69 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Density
  
  
Density At Room Temperature
1.87 g/cm3
  
99+
8.57 g/cm3
  
99+
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
  
Tensile Strength
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
  
Symbol
Fr
  
Nb
  
Period Number
7
  
5
  
Atomic Volume
Not Available
  
10.87 cm3/mol
  
99+
Electron Configuration
[Rn] 7s1
  
[Kr] 4d4 5s1
  
Valence Electron Potential
8.00 (-eV)
  
99+
104.00 (-eV)
  
8
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Radius of an Atom
  
  
Atomic Radius
Not Available
  
Lattice Constant
Not Available
  
Lattice Angles
NA
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
152.00 nΩ·m
  
23
Electrical Conductivity
0.03 106/cm Ω
  
40
0.07 106/cm Ω
  
28
Electron Affinity
Not Available
  
86.10 kJ/mol
  
12
Magnetic Characteristics
  
  
Specific Gravity
Not Available
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
Not Available
  
0.26 J/(kg K)
  
20
Thermal Conductivity
15.00 W/m·K
  
99+
53.70 W/m·K
  
29
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
Not Available
  
24.60 J/mol·K
  
99+
Thermal Expansion
Not Available
  
7.30 µm/(m·K)
  
99+
Standard Molar Entropy
Not Available
  
36.40 J/mol.K
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
696.60 kJ/mol
  
4
Enthalpy of Fusion
Not Available
  
27.20 kJ/mol
  
6
Enthalpy of Atomization
71.00 kJ/mol
  
99+
745.00 kJ/mol
  
4