Properties of Chromium and Hafnium
Melting Point
1,857.00 °C
  
14
2,150.00 °C
  
10
Boiling Point
2,672.00 °C
  
39
Hardness
  
  
Brinell Hardness
1,450.00 MPa
  
6
Vickers Hardness
1,060.00 MPa
  
10
1,520.00 MPa
  
5
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Not Available
  
Speed of Sound
5,940.00 m/s
  
5
3,010.00 m/s
  
27
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Cr
  
Hf
  
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
26,130.00 kJ/mol
  
1
658.50 kJ/mol
  
40
2nd Energy Level
28,750.00 kJ/mol
  
1
1,440.00 kJ/mol
  
99+
3rd Energy Level
34,230.00 kJ/mol
  
1
2,250.00 kJ/mol
  
99+
Electrochemical Equivalent
0.32 g/amp-hr
  
99+
1.66 g/amp-hr
  
99+
Other Chemical Properties
Density
  
  
Density At Room Temperature
7.19 g/cm3
  
99+
13.31 g/cm3
  
26
Density When Liquid (at m.p.)
12.00 g/cm3
  
12
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
NA
  
Symbol
Cr
  
Hf
  
Period Number
4
  
6
  
Atomic Volume
7.23 cm3/mol
  
99+
13.60 cm3/mol
  
38
Electron Configuration
[Ar] 3d5 4s1
  
[Xe] 4f14 5d2 6s2
  
Valence Electron Potential
170.00 (-eV)
  
4
81.00 (-eV)
  
16
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.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
125.00 nΩ·m
  
27
331.00 nΩ·m
  
14
Electrical Conductivity
0.08 106/cm Ω
  
25
0.03 106/cm Ω
  
39
Electron Affinity
64.30 kJ/mol
  
15
0.00 kJ/mol
  
40
Electrical Property
NA
  
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.45 J/(kg K)
  
12
0.14 J/(kg K)
  
37
Thermal Conductivity
93.90 W/m·K
  
17
23.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
23.35 J/mol·K
  
99+
25.73 J/mol·K
  
36
Thermal Expansion
4.90 µm/(m·K)
  
99+
5.90 µm/(m·K)
  
99+
Standard Molar Entropy
23.80 J/mol.K
  
99+
43.60 J/mol.K
  
34
Enthalpy
  
  
Enthalpy of Vaporization
348.80 kJ/mol
  
24
661.10 kJ/mol
  
5
Enthalpy of Fusion
15.31 kJ/mol
  
20
25.10 kJ/mol
  
8
Enthalpy of Atomization
397.50 kJ/mol
  
21
703.00 kJ/mol
  
5