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Cobalt vs Chromium


Chromium vs Cobalt


Periodic Table

Symbol
Co   
Cr   

Group Number
9   
9
6   
12

Period Number
4   
4   

Block
d block   
d block   

Element Family
Transition Metal   
Transition Metal   

CAS Number
7440484   
38
7440473   
39

Space Group Name
P63/mmc   
Im_ 3m   

Space Group Number
194.00   
5
229.00   
1

Facts

Interesting Facts
  • The main source of Cobalt is as a by-product of copper and nickel metal mining.
  • Cobalt metal can be obtained from other elements like Oxygen, Sulfur and Arsenic.
  • It s also used in electroplating process as it exhibits anti cession properties.
  
  • Chromium is highly reactive, hence it is not found free in nature.
  • Ores of Chromites mineral are the major source of Chromium metal.
  • Almost 90% leather tanning is done with the help of chromium.
  

Sources
Found in Compounds, Mining, Ores of Minerals   
Found in Minerals, Mining, Ores of metals, Ores of Minerals   

History
  
  

Who Discovered
Georg Brandt   
Louis Nicolas Vauquelin   

Discovery
In 1732   
In Between 1797 - 1798   

Abundance
  
  

Abundance In Universe
3 * 10-4 %   
9
1.5 * 10-3 %   
7

Abundance In Sun
~0.0004 %   
9
~0.002 %   
7

Abundance In Meteorites
0.06 %   
10
0.30 %   
7

Abundance In Earth's Crust
0.00 %   
21
0.01 %   
13

Abundance In Oceans
0.00 %   
20
0.00 %   
16

Abundance In Humans
0.00 %   
17
0.00 %   
16

Uses

Uses & Benefits
  • Its alloys with aluminum and nickel are used to make powerful magnets.
  • Few other alloys exhibit high-temperature strength and hence they are used in Turbines of Jet and Gas engine.
  
  • It is used to harden the steel and produces a stainless steel and other various alloys.
  • It is also used to give proper finish to polished mirrors. Its chromium plates are used in bathroom fittings.
  

Industrial Uses
Chemical Industry, Electrical Industry, Electronic Industry   
Automobile Industry, Chemical Industry   

Medical Uses
Pharmaceutical Industry   
NA   

Other Uses
Alloys   
Alloys   

Biological Properties
  
  

Toxicity
Toxic   
Highly Toxic   

Present in Human Body
Yes   
Yes   

In Blood
0.04 Blood/mg dm-3   
18
0.11 Blood/mg dm-3   
12

In Bone
0.04 p.p.m.   
27
0.33 p.p.m.   
21

Physical Properties

Melting Point
1,495.00 °C   
29
1,857.00 °C   
14

Boiling Point
2,870.00 °C   
34
2,672.00 °C   
39

Appearance
  
  

Physical State
Solid   
Solid   

Color
Gray   
Silver   

Luster
Metallic   
Metallic   

Hardness
  
  

Mohs Hardness
5.00   
8
8.50   
1

Brinell Hardness
470.00 MPa   
26
687.00 MPa   
16

Vickers Hardness
1,043.00 MPa   
11
1,060.00 MPa   
10

Speed of Sound
4,720.00 m/s   
14
5,940.00 m/s   
5

Optical Properties
  
  

Reflectivity
67.00 %   
11
Not Available   

Allotropes
Yes   
No   

α Allotropes
α-Cobalt   
Not Available   

β Allotropes
β-Cobalt   
Not Available   

γ Allotropes
Not Available   
Not Available   

Chemical Properties

Chemical Formula
Co   
Cr   

Isotopes
  
  

Known Isotopes
26   
13
21   
18

Electronegativity
  
  

Pauling Electronegativity
1.88   
12
1.66   
18

Sanderson Electronegativity
2.56   
1
1.66   
14

Allred Rochow Electronegativity
1.70   
5
1.56   
10

Allen Electronegativity
1.84   
10
1.65   
19

Electropositivity
  
  

Pauling Electropositivity
2.12   
99+
2.34   
36

Ionization Energies
  
  

1st Energy Level
760.40 kJ/mol   
19
26,130.00 kJ/mol   
1

2nd Energy Level
1,648.00 kJ/mol   
31
28,750.00 kJ/mol   
1

3rd Energy Level
3,232.00 kJ/mol   
22
34,230.00 kJ/mol   
1

4th Energy Level
4,950.00 kJ/mol   
19
37,066.00 kJ/mol   
1

5th Energy Level
7,670.00 kJ/mol   
12
97,510.00 kJ/mol   
1

6th Energy Level
9,840.00 kJ/mol   
12
105,800.00 kJ/mol   
1

7th Energy level
12,440.00 kJ/mol   
11
114,300.00 kJ/mol   
1

8th Energy Level
15,230.00 kJ/mol   
12
125,300.00 kJ/mol   
1

9th Energy Level
17,959.00 kJ/mol   
13
134,700.00 kJ/mol   
1

10th Energy Level
26,570.00 kJ/mol   
7
144,300.00 kJ/mol   
1

11th Energy Level
29,400.00 kJ/mol   
8
26,130.00 kJ/mol   
12

12th Energy Level
32,400.00 kJ/mol   
8
28,750.00 kJ/mol   
13

13th Energy Level
36,600.00 kJ/mol   
8
34,230.00 kJ/mol   
10

14th Energy Level
39,700.00 kJ/mol   
9
37,066.00 kJ/mol   
12

15th Energy Level
42,800.00 kJ/mol   
12
97,510.00 kJ/mol   
1

16th Energy Level
49,396.00 kJ/mol   
11
105,800.00 kJ/mol   
2

17th Energy Level
52,737.00 kJ/mol   
13
114,300.00 kJ/mol   
3

18th Energy Level
134,810.00 kJ/mol   
1
125,300.00 kJ/mol   
4

19th Energy Level
145,170.00 kJ/mol   
2
134,700.00 kJ/mol   
5

20th Energy Level
154,700.00 kJ/mol   
4
144,300.00 kJ/mol   
7

21st Energy Level
167,400.00 kJ/mol   
4
157,700.00 kJ/mol   
7

22nd Energy Level
178,100.00 kJ/mol   
3
166,090.00 kJ/mol   
6

23rd Energy Level
189,300.00 kJ/mol   
3
Not Available   

Electrochemical Equivalent
1.10 g/amp-hr   
99+
0.32 g/amp-hr   
99+

Electron Work Function
5.00 eV   
5
4.50 eV   
14

Other Chemical Properties
Chemical Stability, Ionization   
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility   

Atomic Properties

Atomic Number
22   
99+
24   
99+

Electron Configuration
[Ar] 3d2 4s2   
[Ar] 3d5 4s1   

Crystal Structure
Hexagonal Close Packed (HCP)   
Body Centered Cubic (BCC)   

Crystal Lattice
HCP-Crystal-Structure-of-Cobalt.jpg#100   
BCC-Crystal-Structure-.jpg#100   

Atom
  
  

Number of Protons
22   
99+
24   
99+

Number of Neutrons
26   
99+
28   
99+

Number of Electrons
22   
99+
24   
99+

Radius of an Atom
  
  

Atomic Radius
147.00 pm   
34
128.00 pm   
99+

Covalent Radius
160.00 pm   
30
139.00 pm   
99+

Van der Waals Radius
200.00 pm   
28
200.00 pm   
28

Atomic Weight
47.87 amu   
99+
52.00 amu   
99+

Atomic Volume
10.64 cm3/mol   
99+
7.23 cm3/mol   
99+

Adjacent Atomic Numbers
  
  

Previous Element
Iron
  
Vanadium
  

Next Element
Nickel
  
Manganese
  

Valence Electron Potential
95.20 (-eV)   
10
170.00 (-eV)   
4

Lattice Constant
295.08 pm   
99+
291.00 pm   
99+

Lattice Angles
π/2, π/2, 2 π/3   
π/2, π/2, π/2   

Lattice C/A Ratio
Not Available   
Not Available   

Mechanical Properties

Density
  
  

Density At Room Temperature
4.51 g/cm3   
99+
7.19 g/cm3   
99+

Density When Liquid (at m.p.)
4.11 g/cm3   
99+
6.30 g/cm3   
40

Tensile Strength
434.00 MPa   
9
689.00 MPa   
7

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Vapor Pressure at 1000 K
Not Available   
0.00 (Pa)   
24

Vapor Pressure at 2000 K
0.98 (Pa)   
14
774.00 (Pa)   
1

Elasticity properties
  
  

Shear Modulus
44.00 GPa   
17
115.00 GPa   
9

Bulk Modulus
110.00 GPa   
15
160.00 GPa   
11

Young's Modulus
116.00 GPa   
18
279.00 GPa   
8

Poisson Ratio
0.32   
12
0.21   
32

Other Mechanical Properties
Ductile   
NA   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
4,500.00   
1
7.19   
99+

Magnetic Ordering
Paramagnetic   
Antiferromagnetic   

Electrical Properties
  
  

Electrical Property
Poor Conductor   
NA   

Resistivity
420.00 nΩ·m   
12
125.00 nΩ·m   
27

Electrical Conductivity
0.02 106/cm Ω   
99+
0.08 106/cm Ω   
25

Electron Affinity
7.60 kJ/mol   
37
64.30 kJ/mol   
15

Thermal Properties

Specific Heat
0.52 J/(kg K)   
9
0.45 J/(kg K)   
12

Molar Heat Capacity
25.06 J/mol·K   
99+
23.35 J/mol·K   
99+

Thermal Conductivity
21.90 W/m·K   
99+
93.90 W/m·K   
17

Critical Temperature
Not Available   
Not Available   

Thermal Expansion
8.60 µm/(m·K)   
99+
4.90 µm/(m·K)   
99+

Enthalpy
  
  

Enthalpy of Vaporization
429.00 kJ/mol   
15
348.80 kJ/mol   
24

Enthalpy of Fusion
15.48 kJ/mol   
19
15.31 kJ/mol   
20

Enthalpy of Atomization
468.60 kJ/mol   
15
397.50 kJ/mol   
21

Standard Molar Entropy
27.30 J/mol.K   
99+
23.80 J/mol.K   
99+

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