Symbol
Cs
  
Fr
  
Period Number
6
  
7
  
Block
s block
  
s block
  
Element Family
Alkali
  
Alkali
  
Space Group Name
Im_ 3m
  
Not Available
  
Space Group Number
Not Available
  
Interesting Facts
Not Available
  
- 223 Francium has the longest half life at 21.8.
- Francium metal is produced by alpha decay in 227Actinium 227.
  
Sources
Earth's crust, Found in Minerals, Mining, Ores of Minerals
  
Formed by Decay Process, Mining
  
History
  
  
Who Discovered
Robert Bunsen and Gustav Kirchhoff
  
Marguerite Perey
  
Discovery
In 1860
  
In 1939
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~0.0000008 %
  
20
~-9999 %
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Abundance In Oceans
Not Available
  
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.
  
- Francium has no known uses as it has a half life of only 22 minutes.
  
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
  
NA
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
NA
  
Biological Properties
  
  
Toxicity
Mildly Toxic
  
NA
  
Present in Human Body
Yes
  
No
  
In Blood
0.00 Blood/mg dm-3
  
28
0.00 Blood/mg dm-3
  
37
In Bone
0.05 p.p.m.
  
26
0.00 p.p.m.
  
36
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery Gold
  
NA
  
Luster
NA
  
NA
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
Speed of Sound
Not Available
  
Not Available
  
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
  
Fr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
375.70 kJ/mol
  
99+
380.00 kJ/mol
  
99+
2nd Energy Level
2,234.30 kJ/mol
  
8
Not Available
  
3rd Energy Level
3,400.00 kJ/mol
  
16
Not Available
  
Electrochemical Equivalent
4.96 g/amp-hr
  
3
8.32 g/amp-hr
  
1
Electron Work Function
Not Available
  
Other Chemical Properties
Chemical Stability, Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Electron Configuration
[Xe] 6s1
  
[Rn] 7s1
  
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 Radius
Not Available
  
Atomic Weight
132.91 amu
  
99+
Atomic Volume
71.07 cm3/mol
  
1
Not Available
  
Adjacent Atomic Numbers
  
  
Valence Electron Potential
8.62 (-eV)
  
99+
8.00 (-eV)
  
99+
Lattice Constant
Not Available
  
Lattice Angles
π/2, π/2, π/2
  
NA
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
1.93 g/cm3
  
99+
1.87 g/cm3
  
99+
Density When Liquid (at m.p.)
1.84 g/cm3
  
99+
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Not Available
  
Other Mechanical Properties
Ductile
  
NA
  
Magnetic Characteristics
  
  
Specific Gravity
Not Available
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Semiconductor
  
Poor Conductor
  
Resistivity
205.00 nΩ·m
  
17
Electrical Conductivity
0.05 106/cm Ω
  
35
0.03 106/cm Ω
  
40
Electron Affinity
45.50 kJ/mol
  
25
Not Available
  
Specific Heat
0.24 J/(kg K)
  
23
Not Available
  
Molar Heat Capacity
32.21 J/mol·K
  
4
Not Available
  
Thermal Conductivity
35.90 W/m·K
  
36
15.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Thermal Expansion
97.00 µm/(m·K)
  
1
Not Available
  
Enthalpy
  
  
Enthalpy of Vaporization
65.90 kJ/mol
  
99+
Not Available
  
Enthalpy of Fusion
2.10 kJ/mol
  
99+
Not Available
  
Enthalpy of Atomization
78.20 kJ/mol
  
99+
71.00 kJ/mol
  
99+
Standard Molar Entropy
85.20 J/mol.K
  
3
Not Available