Properties of Chromium and Cobalt
Melting Point
1,857.00 °C
  
14
1,495.00 °C
  
29
Boiling Point
2,672.00 °C
  
39
2,870.00 °C
  
34
Hardness
  
  
Vickers Hardness
1,060.00 MPa
  
10
1,043.00 MPa
  
11
Optical Properties
  
  
Refractive Index
Not Available
  
Not Available
  
Reflectivity
Not Available
  
Speed of Sound
5,940.00 m/s
  
5
4,720.00 m/s
  
14
Allotropes
No
  
Yes
  
α Allotropes
Not Available
  
β Allotropes
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Cr
  
Co
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
26,130.00 kJ/mol
  
1
760.40 kJ/mol
  
19
2nd Energy Level
28,750.00 kJ/mol
  
1
1,648.00 kJ/mol
  
31
3rd Energy Level
34,230.00 kJ/mol
  
1
3,232.00 kJ/mol
  
22
Electrochemical Equivalent
0.32 g/amp-hr
  
99+
1.10 g/amp-hr
  
99+
Other Chemical Properties
Density
  
  
Density At Room Temperature
7.19 g/cm3
  
99+
4.51 g/cm3
  
99+
Density When Liquid (at m.p.)
4.11 g/cm3
  
99+
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Viscosity
Not Available
  
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
NA
  
Symbol
Cr
  
Co
  
Period Number
4
  
4
  
Atomic Volume
7.23 cm3/mol
  
99+
10.64 cm3/mol
  
99+
Electron Configuration
[Ar] 3d5 4s1
  
[Ar] 3d2 4s2
  
Valence Electron Potential
170.00 (-eV)
  
4
95.20 (-eV)
  
10
Atom
  
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
HCP-Crystal-Structure-of-Cobalt.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
  
Not Available
  
Adjacent Atomic Numbers
  
  
Electrical Properties
  
  
Resistivity
125.00 nΩ·m
  
27
420.00 nΩ·m
  
12
Electrical Conductivity
0.08 106/cm Ω
  
25
0.02 106/cm Ω
  
99+
Electron Affinity
64.30 kJ/mol
  
15
7.60 kJ/mol
  
37
Electrical Property
NA
  
Magnetic Characteristics
  
  
Permeability
Not Available
  
Not Available
  
Susceptibility
Not Available
  
Not Available
  
Specific Heat
0.45 J/(kg K)
  
12
0.52 J/(kg K)
  
9
Thermal Conductivity
93.90 W/m·K
  
17
21.90 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Molar Heat Capacity
23.35 J/mol·K
  
99+
25.06 J/mol·K
  
99+
Thermal Expansion
4.90 µm/(m·K)
  
99+
8.60 µm/(m·K)
  
99+
Standard Molar Entropy
23.80 J/mol.K
  
99+
27.30 J/mol.K
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
348.80 kJ/mol
  
24
429.00 kJ/mol
  
15
Enthalpy of Fusion
15.31 kJ/mol
  
20
15.48 kJ/mol
  
19
Enthalpy of Atomization
397.50 kJ/mol
  
21
468.60 kJ/mol
  
15