Symbol
Cr
  
Fe
  
Period Number
4
  
4
  
Block
d block
  
d block
  
Element Family
Transition Metal
  
Transition Metal
  
Space Group Name
Im_ 3m
  
Im_ 3m
  
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.
  
- Iron is not always magnetic in nature, its allotrope are ferromagnetic and the B allotrope is nonmagnetic.
- The blood consists Iron in hemoglobin molecules to transfer Oxygen in the body.
  
Sources
Found in Minerals, Mining, Ores of metals, Ores of Minerals
  
Earth's crust, Found in Minerals
  
History
  
  
Who Discovered
Louis Nicolas Vauquelin
  
Unknown
  
Discovery
In Between 1797 - 1798
  
Before 5000 BC
  
Abundance
  
  
Abundance In Universe
1.5 * 10-3 %
  
7
1.1 * 10-1 %
  
1
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.
  
- Iron metal alloy steel is used in the application of civil engineering and manufacturing.
- Alloys of iron with nickel, vanadium, chromium, tungsten and manganese have very useful properties.
  
Industrial Uses
Automobile Industry, Chemical Industry
  
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
Pharmaceutical Industry, Surgical Instruments Manufacturing
  
Other Uses
Alloys
  
Alloys, Sculptures, Statues
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Non Toxic
  
Present in Human Body
Yes
  
Yes
  
In Blood
0.11 Blood/mg dm-3
  
12
447.00 Blood/mg dm-3
  
3
In Bone
0.33 p.p.m.
  
21
380.00 p.p.m.
  
5
Melting Point
1,857.00 °C
  
14
1,535.00 °C
  
25
Boiling Point
2,672.00 °C
  
39
2,750.00 °C
  
37
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Gray
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Vickers Hardness
1,060.00 MPa
  
10
Speed of Sound
5,940.00 m/s
  
5
5,120.00 m/s
  
8
Optical Properties
  
  
Reflectivity
Not Available
  
Allotropes
No
  
Yes
  
α Allotropes
Not Available
  
Ferrite (alpha Iron)
  
β Allotropes
Not Available
  
beta Iron
  
γ Allotropes
Not Available
  
gamma Iron
  
Chemical Formula
Cr
  
Fe
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
26,130.00 kJ/mol
  
1
762.50 kJ/mol
  
17
2nd Energy Level
28,750.00 kJ/mol
  
1
1,561.90 kJ/mol
  
36
3rd Energy Level
34,230.00 kJ/mol
  
1
2,957.00 kJ/mol
  
29
4th Energy Level
37,066.00 kJ/mol
  
1
5,290.00 kJ/mol
  
16
5th Energy Level
97,510.00 kJ/mol
  
1
7,240.00 kJ/mol
  
16
6th Energy Level
105,800.00 kJ/mol
  
1
9,560.00 kJ/mol
  
14
7th Energy level
114,300.00 kJ/mol
  
1
12,060.00 kJ/mol
  
15
8th Energy Level
125,300.00 kJ/mol
  
1
14,580.00 kJ/mol
  
14
9th Energy Level
134,700.00 kJ/mol
  
1
22,540.00 kJ/mol
  
5
10th Energy Level
144,300.00 kJ/mol
  
1
25,290.00 kJ/mol
  
8
11th Energy Level
26,130.00 kJ/mol
  
12
28,000.00 kJ/mol
  
9
12th Energy Level
28,750.00 kJ/mol
  
13
31,920.00 kJ/mol
  
9
13th Energy Level
34,230.00 kJ/mol
  
10
34,830.00 kJ/mol
  
9
14th Energy Level
37,066.00 kJ/mol
  
12
37,840.00 kJ/mol
  
11
15th Energy Level
97,510.00 kJ/mol
  
1
44,100.00 kJ/mol
  
11
16th Energy Level
105,800.00 kJ/mol
  
2
47,206.00 kJ/mol
  
13
17th Energy Level
114,300.00 kJ/mol
  
3
122,200.00 kJ/mol
  
1
18th Energy Level
125,300.00 kJ/mol
  
4
131,000.00 kJ/mol
  
2
19th Energy Level
134,700.00 kJ/mol
  
5
140,500.00 kJ/mol
  
3
20th Energy Level
144,300.00 kJ/mol
  
7
152,600.00 kJ/mol
  
5
21st Energy Level
157,700.00 kJ/mol
  
7
163,000.00 kJ/mol
  
5
22nd Energy Level
166,090.00 kJ/mol
  
6
173,600.00 kJ/mol
  
4
23rd Energy Level
Not Available
  
188,100.00 kJ/mol
  
4
24th Energy Level
Not Available
  
195,200.00 kJ/mol
  
1
Electrochemical Equivalent
0.32 g/amp-hr
  
99+
0.69 g/amp-hr
  
99+
Other Chemical Properties
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
  
Corrosion, Ionization, Solubility
  
Electron Configuration
[Ar] 3d5 4s1
  
[Ar] 3d6 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+
7.10 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
170.00 (-eV)
  
4
67.00 (-eV)
  
20
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+
7.87 g/cm3
  
99+
Density When Liquid (at m.p.)
Tensile Strength
11,000.00 MPa
  
1
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Other Mechanical Properties
NA
  
Ductile, Malleable, Weldable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Antiferromagnetic
  
Ferromagnetic
  
Permeability
Not Available
  
6.3 * 10
-3 H/m
  
1
Susceptibility
Not Available
  
Electrical Properties
  
  
Electrical Property
NA
  
Conductor
  
Resistivity
125.00 nΩ·m
  
27
Electrical Conductivity
0.08 106/cm Ω
  
25
0.10 106/cm Ω
  
20
Electron Affinity
64.30 kJ/mol
  
15
15.70 kJ/mol
  
34
Specific Heat
0.45 J/(kg K)
  
12
0.44 J/(kg K)
  
13
Molar Heat Capacity
23.35 J/mol·K
  
99+
25.10 J/mol·K
  
99+
Thermal Conductivity
93.90 W/m·K
  
17
80.40 W/m·K
  
22
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
4.90 µm/(m·K)
  
99+
11.80 µm/(m·K)
  
33
Enthalpy
  
  
Enthalpy of Vaporization
348.80 kJ/mol
  
24
351.00 kJ/mol
  
23
Enthalpy of Fusion
15.31 kJ/mol
  
20
14.90 kJ/mol
  
22
Enthalpy of Atomization
397.50 kJ/mol
  
21
414.20 kJ/mol
  
19
Standard Molar Entropy
23.80 J/mol.K
  
99+
27.30 J/mol.K
  
99+