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Hafnium vs Chromium

Hafnium
Chromium
Chromium vs Hafnium


Periodic Table
Symbol
Hf   
Cr   
Group Number
4   
14
6   
12
Period Number
6   
4   
Block
d block   
d block   
Element Family
Transition Metal   
Transition Metal   
CAS Number
7440586   
30
7440473   
39
Space Group Name
P63/mmc   
Im_ 3m   
Space Group Number
194.00   
5
229.00   
1
Facts
Interesting Facts
  • Hafnium metal is highly reactive, hence not found free in nature.
  • Hafnium metal as predicated after Mendeleev finished his periodic table.
  
  • 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
By-product Zirconium Refining   
Found in Minerals, Mining, Ores of metals, Ores of Minerals   
History
  
  
Who Discovered
Dirk Coster and George de Hevesy   
Louis Nicolas Vauquelin   
Discovery
In 1922   
In Between 1797 - 1798   
Abundance
  
  
Abundance In Universe
7 * 10-8 %   
25
1.5 * 10-3 %   
7
Abundance In Sun
~0.0000001 %   
26
~0.002 %   
7
Abundance In Meteorites
0.00 %   
37
0.30 %   
7
Abundance In Earth's Crust
0.00 %   
31
0.01 %   
13
Abundance In Oceans
0.00 %   
27
0.00 %   
16
Abundance In Humans
Not Available   
0.00 %   
16
Uses
Uses & Benefits
  • It has an ability to absorb neutrons and hence it is used to make control rods in nuclear submarines. And this metal is also used in Plasma welding torches.
  • It alloys with iron, titanium and niobium are very useful.
  
  • 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
Ammunition Industry   
Automobile Industry, Chemical Industry   
Medical Uses
NA   
NA   
Other Uses
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes   
Alloys   
Biological Properties
  
  
Toxicity
Toxic   
Highly Toxic   
Present in Human Body
No   
Yes   
In Blood
Not Available   
0.11 Blood/mg dm-3   
12
In Bone
Not Available   
0.33 p.p.m.   
21
Physical Properties
Melting Point
2,150.00 °C   
10
1,857.00 °C   
14
Boiling Point
5,400.00 °C   
5
2,672.00 °C   
39
Appearance
  
  
Physical State
Solid   
Solid   
Color
Gray   
Silver   
Luster
Metallic   
Metallic   
Hardness
  
  
Mohs Hardness
5.50   
7
8.50   
1
Brinell Hardness
1,450.00 MPa   
6
687.00 MPa   
16
Vickers Hardness
1,520.00 MPa   
5
1,060.00 MPa   
10
Speed of Sound
3,010.00 m/s   
27
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 Properties
Chemical Formula
Hf   
Cr   
Isotopes
  
  
Known Isotopes
32   
7
21   
18
Electronegativity
  
  
Pauling Electronegativity
1.30   
32
1.66   
18
Sanderson Electronegativity
Not Available   
1.66   
14
Allred Rochow Electronegativity
1.23   
25
1.56   
10
Allen Electronegativity
1.16   
37
1.65   
19
Electropositivity
  
  
Pauling Electropositivity
2.70   
22
2.34   
36
Ionization Energies
  
  
1st Energy Level
658.50 kJ/mol   
40
26,130.00 kJ/mol   
1
2nd Energy Level
1,440.00 kJ/mol   
99+
28,750.00 kJ/mol   
1
3rd Energy Level
2,250.00 kJ/mol   
99+
34,230.00 kJ/mol   
1
4th Energy Level
3,216.00 kJ/mol   
99+
37,066.00 kJ/mol   
1
5th Energy Level
Not Available   
97,510.00 kJ/mol   
1
6th Energy Level
Not Available   
105,800.00 kJ/mol   
1
7th Energy level
Not Available   
114,300.00 kJ/mol   
1
8th Energy Level
Not Available   
125,300.00 kJ/mol   
1
9th Energy Level
Not Available   
134,700.00 kJ/mol   
1
10th Energy Level
Not Available   
144,300.00 kJ/mol   
1
11th Energy Level
Not Available   
26,130.00 kJ/mol   
12
12th Energy Level
Not Available   
28,750.00 kJ/mol   
13
13th Energy Level
Not Available   
34,230.00 kJ/mol   
10
14th Energy Level
Not Available   
37,066.00 kJ/mol   
12
15th Energy Level
Not Available   
97,510.00 kJ/mol   
1
16th Energy Level
Not Available   
105,800.00 kJ/mol   
2
17th Energy Level
Not Available   
114,300.00 kJ/mol   
3
18th Energy Level
Not Available   
125,300.00 kJ/mol   
4
19th Energy Level
Not Available   
134,700.00 kJ/mol   
5
20th Energy Level
Not Available   
144,300.00 kJ/mol   
7
21st Energy Level
Not Available   
157,700.00 kJ/mol   
7
22nd Energy Level
Not Available   
166,090.00 kJ/mol   
6
Electrochemical Equivalent
1.66 g/amp-hr   
99+
0.32 g/amp-hr   
99+
Electron Work Function
3.90 eV   
27
4.50 eV   
14
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility   
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility   
Atomic Properties
Atomic Number
72   
99+
24   
99+
Electron Configuration
[Xe] 4f14 5d2 6s2   
[Ar] 3d5 4s1   
Crystal Structure
Hexagonal Close Packed (HCP)   
Body Centered Cubic (BCC)   
Crystal Lattice
BCC-Crystal-Structure-.jpg#100   
BCC-Crystal-Structure-.jpg#100   
Atom
  
  
Number of Protons
72   
99+
24   
99+
Number of Neutrons
106   
29
28   
99+
Number of Electrons
72   
99+
24   
99+
Radius of an Atom
  
  
Atomic Radius
159.00 pm   
28
128.00 pm   
99+
Covalent Radius
175.00 pm   
23
139.00 pm   
99+
Van der Waals Radius
200.00 pm   
28
200.00 pm   
28
Atomic Weight
178.49 amu   
39
52.00 amu   
99+
Atomic Volume
13.60 cm3/mol   
38
7.23 cm3/mol   
99+
Adjacent Atomic Numbers
  
  
Previous Element
Lutetium
  
Vanadium
  
Next Element
Tantalum
  
Manganese
  
Valence Electron Potential
81.00 (-eV)   
16
170.00 (-eV)   
4
Lattice Constant
319.64 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
1.58   
12
Not Available   
Mechanical Properties
Density
  
  
Density At Room Temperature
13.31 g/cm3   
26
7.19 g/cm3   
99+
Density When Liquid (at m.p.)
12.00 g/cm3   
12
6.30 g/cm3   
40
Tensile Strength
445.00 MPa   
8
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
0.00 (Pa)   
24
774.00 (Pa)   
1
Elasticity properties
  
  
Shear Modulus
30.00 GPa   
23
115.00 GPa   
9
Bulk Modulus
110.00 GPa   
15
160.00 GPa   
11
Young's Modulus
78.00 GPa   
25
279.00 GPa   
8
Poisson Ratio
0.37   
7
0.21   
32
Other Mechanical Properties
Ductile, Malleable   
NA   
Magnetic Properties
Magnetic Characteristics
  
  
Specific Gravity
13.31   
18
7.19   
99+
Magnetic Ordering
Paramagnetic   
Antiferromagnetic   
Electrical Properties
  
  
Electrical Property
Conductor   
NA   
Resistivity
331.00 nΩ·m   
14
125.00 nΩ·m   
27
Electrical Conductivity
0.03 106/cm Ω   
39
0.08 106/cm Ω   
25
Electron Affinity
0.00 kJ/mol   
40
64.30 kJ/mol   
15
Thermal Properties
Specific Heat
0.14 J/(kg K)   
37
0.45 J/(kg K)   
12
Molar Heat Capacity
25.73 J/mol·K   
36
23.35 J/mol·K   
99+
Thermal Conductivity
23.00 W/m·K   
99+
93.90 W/m·K   
17
Critical Temperature
Not Available   
Not Available   
Thermal Expansion
5.90 µm/(m·K)   
99+
4.90 µm/(m·K)   
99+
Enthalpy
  
  
Enthalpy of Vaporization
661.10 kJ/mol   
5
348.80 kJ/mol   
24
Enthalpy of Fusion
25.10 kJ/mol   
8
15.31 kJ/mol   
20
Enthalpy of Atomization
703.00 kJ/mol   
5
397.50 kJ/mol   
21
Standard Molar Entropy
43.60 J/mol.K   
34
23.80 J/mol.K   
99+
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