Symbol
Ce
  
Hf
  
Group Number
Not Available
  
Period Number
6
  
6
  
Block
f block
  
d block
  
Element Family
Lanthanide
  
Transition Metal
  
Space Group Name
P63/mmc
  
P63/mmc
  
Interesting Facts
- Cerium is a rare earth metal but still it is not rare at all.
- It’s non-toxic compound Cerium sulfide has a rich red color and it is used as a pigment.
- Cerium metal is also used in Flat screen TVs, light bulb, floodlights, etc.
  
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
Sources
Found in Minerals, Mining, Ores of Minerals
  
By-product Zirconium Refining
  
History
  
  
Who Discovered
Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
  
Dirk Coster and George de Hevesy
  
Discovery
In 1803
  
In 1922
  
Abundance
  
  
Abundance In Sun
~0.0000004 %
  
23
~0.0000001 %
  
26
Abundance In Earth's Crust
Uses & Benefits
- It is used to include flints for cigarette lighters.
- Its compound Cerium (Ill) Oxide is used as a catalyst; it is put inside the walls of the oven as it prevents from the buildup of cooking residues.
  
- 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.
  
Industrial Uses
Chemical Industry
  
Ammunition Industry
  
Medical Uses
Medical Research
  
NA
  
Other Uses
Alloys
  
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Biological Properties
  
  
Toxicity
Moderately Toxic
  
Toxic
  
Present in Human Body
Yes
  
No
  
In Blood
0.00 Blood/mg dm-3
  
30
Not Available
  
In Bone
2.70 p.p.m.
  
14
Not Available
  
Melting Point
2,150.00 °C
  
10
Boiling Point
3,257.00 °C
  
23
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Gray
  
Luster
Lustrous
  
Metallic
  
Hardness
  
  
Brinell Hardness
186.00 MPa
  
99+
1,450.00 MPa
  
6
Vickers Hardness
1,520.00 MPa
  
5
Speed of Sound
2,100.00 m/s
  
99+
3,010.00 m/s
  
27
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
Ce
  
Hf
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
534.40 kJ/mol
  
99+
658.50 kJ/mol
  
40
2nd Energy Level
1,050.00 kJ/mol
  
99+
1,440.00 kJ/mol
  
99+
3rd Energy Level
1,949.00 kJ/mol
  
99+
2,250.00 kJ/mol
  
99+
4th Energy Level
3,547.00 kJ/mol
  
99+
3,216.00 kJ/mol
  
99+
5th Energy Level
6,325.00 kJ/mol
  
22
Not Available
  
6th Energy Level
7,490.00 kJ/mol
  
21
Not Available
  
Electrochemical Equivalent
1.74 g/amp-hr
  
99+
1.66 g/amp-hr
  
99+
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 4f1 5d1 6s2
  
[Xe] 4f14 5d2 6s2
  
Crystal Structure
Double Hexagonal Close Packed (DHCP)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
DHCP-Crystal-Structure-of-Cerium.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
140.12 amu
  
99+
Atomic Volume
20.67 cm3/mol
  
17
13.60 cm3/mol
  
38
Adjacent Atomic Numbers
  
  
Valence Electron Potential
41.78 (-eV)
  
99+
81.00 (-eV)
  
16
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
6.77 g/cm3
  
99+
13.31 g/cm3
  
26
Density When Liquid (at m.p.)
12.00 g/cm3
  
12
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Malleable
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
331.00 nΩ·m
  
14
Electrical Conductivity
0.01 106/cm Ω
  
99+
0.03 106/cm Ω
  
39
Electron Affinity
50.00 kJ/mol
  
21
0.00 kJ/mol
  
40
Specific Heat
0.19 J/(kg K)
  
32
0.14 J/(kg K)
  
37
Molar Heat Capacity
26.94 J/mol·K
  
23
25.73 J/mol·K
  
36
Thermal Conductivity
11.30 W/m·K
  
99+
23.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
6.30 µm/(m·K)
  
99+
5.90 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
414.00 kJ/mol
  
16
661.10 kJ/mol
  
5
Enthalpy of Fusion
5.46 kJ/mol
  
99+
25.10 kJ/mol
  
8
Enthalpy of Atomization
381.00 kJ/mol
  
23
703.00 kJ/mol
  
5
Standard Molar Entropy
72.00 J/mol.K
  
12
43.60 J/mol.K
  
34