Symbol
Cs
  
La
  
Group Number
Not Available
  
Period Number
6
  
6
  
Block
s block
  
f block
  
Element Family
Alkali
  
Lanthanide
  
Space Group Name
Im_ 3m
  
P63/mmc
  
Interesting Facts
Not Available
  
- Lanthanum metal is highly malleable, ductile and sectile.
- If exposed to air Lanthanum metal oxidizes rapidly.
  
Sources
Earth's crust, Found in Minerals, Mining, Ores of Minerals
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Robert Bunsen and Gustav Kirchhoff
  
Carl Gustaf Mosander
  
Discovery
In 1860
  
In 1838
  
Abundance
  
  
Abundance In Sun
~0.0000008 %
  
20
~0.0000002 %
  
25
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
Uses & Benefits
- The most common use of cesium metal is as a drilling fluid. It is also used in optical glass manufacturing.
-
In vacuum tubes and radiation monitor equipment this metal is used as a catalyst promoter.
  
- It has no commercial uses, but its alloys are in high demand. Lanthanum and Nickel alloy is used for the hydrogen gas storage.
- The best-known use for mischmetal alloy of Lanthanum is; as a ‘flints’ for cigarette lighters.
  
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
  
Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys, Mirror Manufacturing
  
Biological Properties
  
  
Toxicity
Mildly Toxic
  
Low Toxic
  
Present in Human Body
Yes
  
Yes
  
In Blood
0.00 Blood/mg dm-3
  
28
Not Available
  
In Bone
0.05 p.p.m.
  
26
0.08 p.p.m.
  
24
Boiling Point
3,469.00 °C
  
18
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery Gold
  
Silvery White
  
Luster
NA
  
NA
  
Hardness
  
  
Vickers Hardness
Not Available
  
Speed of Sound
Not Available
  
2,475.00 m/s
  
37
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
Cs
  
La
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
375.70 kJ/mol
  
99+
538.10 kJ/mol
  
99+
2nd Energy Level
2,234.30 kJ/mol
  
8
1,067.00 kJ/mol
  
99+
3rd Energy Level
3,400.00 kJ/mol
  
16
1,850.30 kJ/mol
  
99+
4th Energy Level
Not Available
  
4,819.00 kJ/mol
  
22
5th Energy Level
Not Available
  
5,940.00 kJ/mol
  
25
Electrochemical Equivalent
4.96 g/amp-hr
  
3
1.73 g/amp-hr
  
99+
Other Chemical Properties
Chemical Stability, Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 6s1
  
[Xe] 5d2 6s2
  
Crystal Structure
Body Centered Cubic (BCC)
  
Double Hexagonal Close Packed (DHCP)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
DHCP-Crystal-Structure-of-Lanthanum.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
132.91 amu
  
99+
138.91 amu
  
99+
Atomic Volume
71.07 cm3/mol
  
1
20.73 cm3/mol
  
16
Adjacent Atomic Numbers
  
  
Valence Electron Potential
8.62 (-eV)
  
99+
40.71 (-eV)
  
99+
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
1.93 g/cm3
  
99+
6.16 g/cm3
  
99+
Density When Liquid (at m.p.)
1.84 g/cm3
  
99+
5.94 g/cm3
  
99+
Tensile Strength
Not Available
  
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
Ductile
  
Ductile
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Semiconductor
  
Conductor
  
Resistivity
205.00 nΩ·m
  
17
Electrical Conductivity
0.05 106/cm Ω
  
35
0.01 106/cm Ω
  
99+
Electron Affinity
45.50 kJ/mol
  
25
48.00 kJ/mol
  
23
Specific Heat
0.24 J/(kg K)
  
23
0.19 J/(kg K)
  
32
Molar Heat Capacity
32.21 J/mol·K
  
4
27.11 J/mol·K
  
21
Thermal Conductivity
35.90 W/m·K
  
36
13.40 W/m·K
  
99+
Critical Temperature
Not Available
  
Thermal Expansion
97.00 µm/(m·K)
  
1
12.10 µm/(m·K)
  
32
Enthalpy
  
  
Enthalpy of Vaporization
65.90 kJ/mol
  
99+
399.60 kJ/mol
  
17
Enthalpy of Fusion
2.10 kJ/mol
  
99+
6.20 kJ/mol
  
99+
Enthalpy of Atomization
78.20 kJ/mol
  
99+
431.00 kJ/mol
  
16
Standard Molar Entropy
85.20 J/mol.K
  
3
56.90 J/mol.K
  
23