Symbol
Fr
  
La
  
Group Number
Not Available
  
Period Number
7
  
6
  
Block
s block
  
f block
  
Element Family
Alkali
  
Lanthanide
  
Space Group Name
Not Available
  
P63/mmc
  
Space Group Number
Not Available
  
Interesting Facts
- 223 Francium has the longest half life at 21.8.
- Francium metal is produced by alpha decay in 227Actinium 227.
  
- Lanthanum metal is highly malleable, ductile and sectile.
- If exposed to air Lanthanum metal oxidizes rapidly.
  
Sources
Formed by Decay Process, Mining
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Marguerite Perey
  
Carl Gustaf Mosander
  
Discovery
In 1939
  
In 1838
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
~0.0000002 %
  
25
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Abundance In Oceans
Not Available
  
Uses & Benefits
- Francium has no known uses as it has a half life of only 22 minutes.
  
- 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
NA
  
Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
NA
  
Other Uses
NA
  
Alloys, Mirror Manufacturing
  
Biological Properties
  
  
Toxicity
NA
  
Low Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
0.00 Blood/mg dm-3
  
37
Not Available
  
In Bone
0.00 p.p.m.
  
36
0.08 p.p.m.
  
24
Boiling Point
3,469.00 °C
  
18
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
NA
  
Silvery White
  
Luster
NA
  
NA
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
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
Fr
  
La
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
380.00 kJ/mol
  
99+
538.10 kJ/mol
  
99+
2nd Energy Level
Not Available
  
1,067.00 kJ/mol
  
99+
3rd Energy Level
Not Available
  
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
8.32 g/amp-hr
  
1
1.73 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Rn] 7s1
  
[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 Radius
Not Available
  
Atomic Weight
138.91 amu
  
99+
Atomic Volume
Not Available
  
20.73 cm3/mol
  
16
Adjacent Atomic Numbers
  
  
Valence Electron Potential
8.00 (-eV)
  
99+
40.71 (-eV)
  
99+
Lattice Constant
Not Available
  
Lattice Angles
NA
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
1.87 g/cm3
  
99+
6.16 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
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
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
Ductile
  
Magnetic Characteristics
  
  
Specific Gravity
Not Available
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Poor Conductor
  
Conductor
  
Electrical Conductivity
0.03 106/cm Ω
  
40
0.01 106/cm Ω
  
99+
Electron Affinity
Not Available
  
48.00 kJ/mol
  
23
Specific Heat
Not Available
  
0.19 J/(kg K)
  
32
Molar Heat Capacity
Not Available
  
27.11 J/mol·K
  
21
Thermal Conductivity
15.00 W/m·K
  
99+
13.40 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
Not Available
  
12.10 µm/(m·K)
  
32
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
399.60 kJ/mol
  
17
Enthalpy of Fusion
Not Available
  
6.20 kJ/mol
  
99+
Enthalpy of Atomization
71.00 kJ/mol
  
99+
431.00 kJ/mol
  
16
Standard Molar Entropy
Not Available
  
56.90 J/mol.K
  
23