Symbol
Cr
  
Mn
  
Period Number
4
  
4
  
Block
d block
  
d block
  
Element Family
Transition Metal
  
Transition Metal
  
Space Group Name
Im_ 3m
  
I_ 43m
  
Interesting Facts
- 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.
  
- Manganese is an essential trace element in all forms of life.
- Manganese metal oxidizes very easily, but it does not fuse that easily.
  
Sources
Found in Minerals, Mining, Ores of metals, Ores of Minerals
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Louis Nicolas Vauquelin
  
Johann Gottlieb Gahn
  
Discovery
In Between 1797 - 1798
  
In 1774
  
Abundance
  
  
Abundance In Universe
1.5 * 10-3 %
  
7
Abundance In Earth's Crust
Uses & Benefits
- 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.
  
- This metal is very brittle hence it mostly not used as a pure metal, but its alloys are very useful
- Its alloy Manganese steel is extremely strong and used in railway tracks, safes, prison bars and riffle barrels.
  
Industrial Uses
Automobile Industry, Chemical Industry
  
Automobile Industry, Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Toxic
  
Present in Human Body
Yes
  
Yes
  
In Blood
0.11 Blood/mg dm-3
  
12
0.08 Blood/mg dm-3
  
14
In Bone
0.33 p.p.m.
  
21
100.00 p.p.m.
  
8
Melting Point
1,857.00 °C
  
14
1,245.00 °C
  
37
Boiling Point
2,672.00 °C
  
39
1,962.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silver
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Brinell Hardness
196.00 MPa
  
99+
Vickers Hardness
1,060.00 MPa
  
10
Not Available
  
Speed of Sound
5,940.00 m/s
  
5
5,150.00 m/s
  
7
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Cr
  
Mn
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
26,130.00 kJ/mol
  
1
717.30 kJ/mol
  
30
2nd Energy Level
28,750.00 kJ/mol
  
1
1,509.00 kJ/mol
  
39
3rd Energy Level
34,230.00 kJ/mol
  
1
3,248.00 kJ/mol
  
21
4th Energy Level
37,066.00 kJ/mol
  
1
4,940.00 kJ/mol
  
20
5th Energy Level
97,510.00 kJ/mol
  
1
6,990.00 kJ/mol
  
17
6th Energy Level
105,800.00 kJ/mol
  
1
9,220.00 kJ/mol
  
16
7th Energy level
114,300.00 kJ/mol
  
1
11,500.00 kJ/mol
  
16
8th Energy Level
125,300.00 kJ/mol
  
1
18,770.00 kJ/mol
  
5
9th Energy Level
134,700.00 kJ/mol
  
1
21,400.00 kJ/mol
  
6
10th Energy Level
144,300.00 kJ/mol
  
1
23,960.00 kJ/mol
  
9
11th Energy Level
26,130.00 kJ/mol
  
12
27,590.00 kJ/mol
  
10
12th Energy Level
28,750.00 kJ/mol
  
13
30,330.00 kJ/mol
  
10
13th Energy Level
34,230.00 kJ/mol
  
10
33,150.00 kJ/mol
  
11
14th Energy Level
37,066.00 kJ/mol
  
12
38,880.00 kJ/mol
  
10
15th Energy Level
97,510.00 kJ/mol
  
1
41,987.00 kJ/mol
  
13
16th Energy Level
105,800.00 kJ/mol
  
2
109,480.00 kJ/mol
  
1
17th Energy Level
114,300.00 kJ/mol
  
3
118,100.00 kJ/mol
  
2
18th Energy Level
125,300.00 kJ/mol
  
4
127,100.00 kJ/mol
  
3
19th Energy Level
134,700.00 kJ/mol
  
5
138,600.00 kJ/mol
  
4
20th Energy Level
144,300.00 kJ/mol
  
7
148,500.00 kJ/mol
  
6
21st Energy Level
157,700.00 kJ/mol
  
7
158,600.00 kJ/mol
  
6
22nd Energy Level
166,090.00 kJ/mol
  
6
172,500.00 kJ/mol
  
5
23rd Energy Level
Not Available
  
181,380.00 kJ/mol
  
5
Electrochemical Equivalent
0.32 g/amp-hr
  
99+
0.29 g/amp-hr
  
99+
Other Chemical Properties
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes
  
Electron Configuration
[Ar] 3d5 4s1
  
[Ar] 3d5 4s2
  
Crystal Structure
Body Centered Cubic (BCC)
  
Body Centered Cubic (BCC)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
7.23 cm3/mol
  
99+
1.39 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
170.00 (-eV)
  
4
220.00 (-eV)
  
2
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
7.19 g/cm3
  
99+
7.21 g/cm3
  
99+
Density When Liquid (at m.p.)
5.95 g/cm3
  
99+
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Antiferromagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
NA
  
Conductor
  
Resistivity
125.00 nΩ·m
  
27
Electrical Conductivity
0.08 106/cm Ω
  
25
0.01 106/cm Ω
  
99+
Electron Affinity
64.30 kJ/mol
  
15
0.00 kJ/mol
  
40
Specific Heat
0.45 J/(kg K)
  
12
0.48 J/(kg K)
  
11
Molar Heat Capacity
23.35 J/mol·K
  
99+
26.32 J/mol·K
  
29
Thermal Conductivity
93.90 W/m·K
  
17
7.81 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
4.90 µm/(m·K)
  
99+
21.70 µm/(m·K)
  
21
Enthalpy
  
  
Enthalpy of Vaporization
348.80 kJ/mol
  
24
219.70 kJ/mol
  
99+
Enthalpy of Fusion
15.31 kJ/mol
  
20
14.64 kJ/mol
  
23
Enthalpy of Atomization
397.50 kJ/mol
  
21
280.30 kJ/mol
  
38
Standard Molar Entropy
23.80 J/mol.K
  
99+
32.00 J/mol.K
  
99+