Symbol
Mn
  
Cr
  
Period Number
4
  
4
  
Block
d block
  
d block
  
Element Family
Transition Metal
  
Transition Metal
  
Space Group Name
I_ 43m
  
Im_ 3m
  
Interesting Facts
- Manganese is an essential trace element in all forms of life.
- Manganese metal oxidizes very easily, but it does not fuse that easily.
  
- 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 Minerals, Mining, Ores of Minerals
  
Found in Minerals, Mining, Ores of metals, Ores of Minerals
  
History
  
  
Who Discovered
Johann Gottlieb Gahn
  
Louis Nicolas Vauquelin
  
Discovery
In 1774
  
In Between 1797 - 1798
  
Abundance
  
  
Abundance In Universe
1.5 * 10-3 %
  
7
Abundance In Earth's Crust
Uses & Benefits
- 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.
  
- 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
Automobile Industry, Electrical Industry, Electronic Industry
  
Automobile Industry, Chemical Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Toxic
  
Highly Toxic
  
Present in Human Body
Yes
  
Yes
  
In Blood
0.08 Blood/mg dm-3
  
14
0.11 Blood/mg dm-3
  
12
In Bone
100.00 p.p.m.
  
8
0.33 p.p.m.
  
21
Melting Point
1,245.00 °C
  
37
1,857.00 °C
  
14
Boiling Point
1,962.00 °C
  
99+
2,672.00 °C
  
39
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silver
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Brinell Hardness
196.00 MPa
  
99+
Vickers Hardness
Not Available
  
1,060.00 MPa
  
10
Speed of Sound
5,150.00 m/s
  
7
5,940.00 m/s
  
5
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
Mn
  
Cr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
717.30 kJ/mol
  
30
26,130.00 kJ/mol
  
1
2nd Energy Level
1,509.00 kJ/mol
  
39
28,750.00 kJ/mol
  
1
3rd Energy Level
3,248.00 kJ/mol
  
21
34,230.00 kJ/mol
  
1
4th Energy Level
4,940.00 kJ/mol
  
20
37,066.00 kJ/mol
  
1
5th Energy Level
6,990.00 kJ/mol
  
17
97,510.00 kJ/mol
  
1
6th Energy Level
9,220.00 kJ/mol
  
16
105,800.00 kJ/mol
  
1
7th Energy level
11,500.00 kJ/mol
  
16
114,300.00 kJ/mol
  
1
8th Energy Level
18,770.00 kJ/mol
  
5
125,300.00 kJ/mol
  
1
9th Energy Level
21,400.00 kJ/mol
  
6
134,700.00 kJ/mol
  
1
10th Energy Level
23,960.00 kJ/mol
  
9
144,300.00 kJ/mol
  
1
11th Energy Level
27,590.00 kJ/mol
  
10
26,130.00 kJ/mol
  
12
12th Energy Level
30,330.00 kJ/mol
  
10
28,750.00 kJ/mol
  
13
13th Energy Level
33,150.00 kJ/mol
  
11
34,230.00 kJ/mol
  
10
14th Energy Level
38,880.00 kJ/mol
  
10
37,066.00 kJ/mol
  
12
15th Energy Level
41,987.00 kJ/mol
  
13
97,510.00 kJ/mol
  
1
16th Energy Level
109,480.00 kJ/mol
  
1
105,800.00 kJ/mol
  
2
17th Energy Level
118,100.00 kJ/mol
  
2
114,300.00 kJ/mol
  
3
18th Energy Level
127,100.00 kJ/mol
  
3
125,300.00 kJ/mol
  
4
19th Energy Level
138,600.00 kJ/mol
  
4
134,700.00 kJ/mol
  
5
20th Energy Level
148,500.00 kJ/mol
  
6
144,300.00 kJ/mol
  
7
21st Energy Level
158,600.00 kJ/mol
  
6
157,700.00 kJ/mol
  
7
22nd Energy Level
172,500.00 kJ/mol
  
5
166,090.00 kJ/mol
  
6
23rd Energy Level
181,380.00 kJ/mol
  
5
Not Available
  
Electrochemical Equivalent
0.29 g/amp-hr
  
99+
0.32 g/amp-hr
  
99+
Other Chemical Properties
Ionization, Radioactive Isotopes
  
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Ar] 3d5 4s2
  
[Ar] 3d5 4s1
  
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
1.39 cm3/mol
  
99+
7.23 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
220.00 (-eV)
  
2
170.00 (-eV)
  
4
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
7.21 g/cm3
  
99+
7.19 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
Paramagnetic
  
Antiferromagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
NA
  
Resistivity
125.00 nΩ·m
  
27
Electrical Conductivity
0.01 106/cm Ω
  
99+
0.08 106/cm Ω
  
25
Electron Affinity
0.00 kJ/mol
  
40
64.30 kJ/mol
  
15
Specific Heat
0.48 J/(kg K)
  
11
0.45 J/(kg K)
  
12
Molar Heat Capacity
26.32 J/mol·K
  
29
23.35 J/mol·K
  
99+
Thermal Conductivity
7.81 W/m·K
  
99+
93.90 W/m·K
  
17
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
21.70 µm/(m·K)
  
21
4.90 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
219.70 kJ/mol
  
99+
348.80 kJ/mol
  
24
Enthalpy of Fusion
14.64 kJ/mol
  
23
15.31 kJ/mol
  
20
Enthalpy of Atomization
280.30 kJ/mol
  
38
397.50 kJ/mol
  
21
Standard Molar Entropy
32.00 J/mol.K
  
99+
23.80 J/mol.K
  
99+