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Francium Rubidium Comparison


Rubidium Francium comparison


Periodic Table

Symbol
Fr   
Rb   

Group Number
1   
17
1   
17

Period Number
7   
5   

Block
s block   
s block   

Element Family
Alkali   
Alkali   

CAS Number
7440735   
18
7440177   
99+

Space Group Name
Not Available   
Im_ 3m   

Space Group Number
Not Available   
229.00   
1

Facts

Interesting Facts
  • 223 Francium has the longest half life at 21.8.
  • Francium metal is produced by alpha decay in 227Actinium 227.
  
  • Rubidium metal is 16th most common element found in the earth crust.
  • Rubidium metal also found in minerals as well as seawater.
  

Sources
Formed by Decay Process, Mining   
Obtained from Lithium Production.   

History
  
  

Who Discovered
Marguerite Perey   
Robert Bunsen and Gustav Kirchhoff   

Discovery
In 1939   
In 1861   

Abundance
  
  

Abundance In Universe
Not Available   
1 * 10-6 %   
16

Abundance In Sun
~-9999 %   
~0.000003 %   
17

Abundance In Meteorites
Not Available   
0.00 %   
19

Abundance In Earth's Crust
Not Available   
0.01 %   
18

Abundance In Oceans
Not Available   
0.00 %   
7

Abundance In Humans
Not Available   
0.00 %   
7

Uses

Uses & Benefits
  • Francium has no known uses as it has a half life of only 22 minutes.
  
  • Rubidium's main application is in the glass manufacturing.
  • Rubidium can very easily get ionized and hence it is used for ion engines, but it is still less efficient than that of Caesium.
  

Industrial Uses
NA   
NA   

Medical Uses
NA   
NA   

Other Uses
NA   
Alloys, Research Purposes   

Biological Properties
  
  

Toxicity
NA   
Non Toxic   

Present in Human Body
No   
Yes   

In Blood
0.00 Blood/mg dm-3   
37
2.49 Blood/mg dm-3   
7

In Bone
0.00 p.p.m.   
36
5.00 p.p.m.   
13

Physical Properties

Melting Point
27.00 °C   
99+
38.89 °C   
99+

Boiling Point
677.00 °C   
99+
688.00 °C   
99+

Appearance
  
  

Physical State
Solid   
Solid   

Color
NA   
Grayish White   

Luster
NA   
NA   

Hardness
  
  

Mohs Hardness
Not Available   
0.30   
24

Brinell Hardness
Not Available   
0.22 MPa   
99+

Speed of Sound
Not Available   
1,300.00 m/s   
99+

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
Fr   
Rb   

Isotopes
  
  

Known Isotopes
33   
6
29   
10

Electronegativity
  
  

Pauling Electronegativity
0.70   
99+
0.82   
99+

Sanderson Electronegativity
Not Available   
0.31   
32

Allred Rochow Electronegativity
0.86   
99+
0.89   
40

Mulliken-Jaffe Electronegativity
0.68   
25
0.69   
24

Allen Electronegativity
0.67   
99+
0.71   
99+

Electropositivity
  
  

Pauling Electropositivity
3.30   
1
3.18   
3

Ionization Energies
  
  

1st Energy Level
380.00 kJ/mol   
99+
403.00 kJ/mol   
99+

2nd Energy Level
Not Available   
2,633.00 kJ/mol   
6

3rd Energy Level
Not Available   
3,860.00 kJ/mol   
11

4th Energy Level
Not Available   
5,080.00 kJ/mol   
18

5th Energy Level
Not Available   
6,850.00 kJ/mol   
19

6th Energy Level
Not Available   
8,140.00 kJ/mol   
20

7th Energy level
Not Available   
9,570.00 kJ/mol   
20

8th Energy Level
Not Available   
13,120.00 kJ/mol   
17

9th Energy Level
Not Available   
14,500.00 kJ/mol   
18

10th Energy Level
Not Available   
26,740.00 kJ/mol   
6

Electrochemical Equivalent
8.32 g/amp-hr   
1
3.19 g/amp-hr   
14

Electron Work Function
Not Available   
2.16 eV   
99+

Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility   
Corrosion, Ionization, Radioactive Isotopes, Radioactivity   

Atomic Properties

Atomic Number
87   
31
37   
99+

Electron Configuration
[Rn] 7s1   
[Kr] 5s1   

Crystal Structure
Body Centered Cubic (BCC)   
Body Centered Cubic (BCC)   

Crystal Lattice
BCC-Crystal-Structure-.jpg#100   
BCC-Crystal-Structure-.jpg#100   

Atom
  
  

Number of Protons
87   
31
37   
99+

Number of Neutrons
136   
17
48   
99+

Number of Electrons
87   
31
37   
99+

Radius of an Atom
  
  

Atomic Radius
Not Available   
248.00 pm   
2

Covalent Radius
260.00 pm   
1
220.00 pm   
4

Van der Waals Radius
348.00 pm   
1
303.00 pm   
3

Atomic Weight
223.00 amu   
27
85.47 amu   
99+

Atomic Volume
Not Available   
55.90 cm3/mol   
2

Adjacent Atomic Numbers
  
  

Previous Element
Polonium
  
Gallium
  

Next Element
Radium
  
Strontium
  

Valence Electron Potential
8.00 (-eV)   
99+
9.47 (-eV)   
99+

Lattice Constant
Not Available   
558.50 pm   
10

Lattice Angles
NA   
π/2, π/2, π/2   

Lattice C/A Ratio
Not Available   
Not Available   

Mechanical Properties

Density
  
  

Density At Room Temperature
1.87 g/cm3   
99+
1.53 g/cm3   
99+

Density When Liquid (at m.p.)
Not Available   
1.46 g/cm3   
99+

Tensile Strength
Not Available   
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Elasticity properties
  
  

Bulk Modulus
Not Available   
2.50 GPa   
99+

Young's Modulus
Not Available   
2.40 GPa   
99+

Poisson Ratio
Not Available   
Not Available   

Other Mechanical Properties
NA   
Ductile   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
Not Available   
1.53   
99+

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Poor Conductor   
Conductor   

Resistivity
3.00 nΩ·m   
99+
128.00 nΩ·m   
26

Electrical Conductivity
0.03 106/cm Ω   
40
0.08 106/cm Ω   
24

Electron Affinity
Not Available   
46.90 kJ/mol   
24

Thermal Properties

Specific Heat
Not Available   
0.36 J/(kg K)   
17

Molar Heat Capacity
Not Available   
31.06 J/mol·K   
5

Thermal Conductivity
15.00 W/m·K   
99+
58.20 W/m·K   
26

Critical Temperature
Not Available   
2,093.00 K   
4

Thermal Expansion
Not Available   
90.00 µm/(m·K)   
2

Enthalpy
  
  

Enthalpy of Vaporization
Not Available   
69.20 kJ/mol   
99+

Enthalpy of Fusion
Not Available   
2.19 kJ/mol   
99+

Enthalpy of Atomization
71.00 kJ/mol   
99+
82.00 kJ/mol   
99+

Standard Molar Entropy
Not Available   
76.80 J/mol.K   
5

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