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Rubidium Cesium Comparison


Cesium Rubidium comparison


Periodic Table

Symbol
Rb   
Cs   

Group Number
1   
17
1   
17

Period Number
5   
6   

Block
s block   
s block   

Element Family
Alkali   
Alkali   

CAS Number
7440177   
99+
7440462   
40

Space Group Name
Im_ 3m   
Im_ 3m   

Space Group Number
229.00   
1
229.00   
1

Facts

Interesting Facts
  • Rubidium metal is 16th most common element found in the earth crust.
  • Rubidium metal also found in minerals as well as seawater.
  
Not Available   

Sources
Obtained from Lithium Production.   
Earth's crust, Found in Minerals, Mining, Ores of Minerals   

History
  
  

Who Discovered
Robert Bunsen and Gustav Kirchhoff   
Robert Bunsen and Gustav Kirchhoff   

Discovery
In 1861   
In 1860   

Abundance
  
  

Abundance In Universe
1 * 10-6 %   
16
8 * 10-8 %   
24

Abundance In Sun
~0.000003 %   
17
~0.0000008 %   
20

Abundance In Meteorites
0.00 %   
19
0.00 %   
38

Abundance In Earth's Crust
0.01 %   
18
0.00 %   
35

Abundance In Oceans
0.00 %   
7
0.00 %   
17

Abundance In Humans
0.00 %   
7
0.00 %   
17

Uses

Uses & Benefits
  • 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.
  
  • 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.
  

Industrial Uses
NA   
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry   

Medical Uses
NA   
NA   

Other Uses
Alloys, Research Purposes   
Alloys   

Biological Properties
  
  

Toxicity
Non Toxic   
Mildly Toxic   

Present in Human Body
Yes   
Yes   

In Blood
2.49 Blood/mg dm-3   
7
0.00 Blood/mg dm-3   
28

In Bone
5.00 p.p.m.   
13
0.05 p.p.m.   
26

Physical Properties

Melting Point
38.89 °C   
99+
28.50 °C   
99+

Boiling Point
688.00 °C   
99+
678.40 °C   
99+

Appearance
  
  

Physical State
Solid   
Solid   

Color
Grayish White   
Silvery Gold   

Luster
NA   
NA   

Hardness
  
  

Mohs Hardness
0.30   
24
0.20   
25

Brinell Hardness
0.22 MPa   
99+
0.14 MPa   
99+

Speed of Sound
1,300.00 m/s   
99+
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 Properties

Chemical Formula
Rb   
Cs   

Isotopes
  
  

Known Isotopes
29   
10
36   
3

Electronegativity
  
  

Pauling Electronegativity
0.82   
99+
0.79   
99+

Sanderson Electronegativity
0.31   
32
0.22   
33

Allred Rochow Electronegativity
0.89   
40
0.86   
99+

Mulliken-Jaffe Electronegativity
0.69   
24
0.62   
26

Allen Electronegativity
0.71   
99+
0.66   
99+

Electropositivity
  
  

Pauling Electropositivity
3.18   
3
3.21   
2

Ionization Energies
  
  

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

2nd Energy Level
2,633.00 kJ/mol   
6
2,234.30 kJ/mol   
8

3rd Energy Level
3,860.00 kJ/mol   
11
3,400.00 kJ/mol   
16

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

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

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

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

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

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

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

Electrochemical Equivalent
3.19 g/amp-hr   
14
4.96 g/amp-hr   
3

Electron Work Function
2.16 eV   
99+
2.14 eV   
99+

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

Atomic Properties

Atomic Number
37   
99+
55   
99+

Electron Configuration
[Kr] 5s1   
[Xe] 6s1   

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
37   
99+
55   
99+

Number of Neutrons
48   
99+
78   
99+

Number of Electrons
37   
99+
55   
99+

Radius of an Atom
  
  

Atomic Radius
248.00 pm   
2
265.00 pm   
1

Covalent Radius
220.00 pm   
4
244.00 pm   
2

Van der Waals Radius
303.00 pm   
3
343.00 pm   
2

Atomic Weight
85.47 amu   
99+
132.91 amu   
99+

Atomic Volume
55.90 cm3/mol   
2
71.07 cm3/mol   
1

Adjacent Atomic Numbers
  
  

Previous Element
Gallium
  
Tin
  

Next Element
Strontium
  
Barium
  

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

Lattice Constant
558.50 pm   
10
614.10 pm   
5

Lattice Angles
π/2, π/2, π/2   
π/2, π/2, π/2   

Lattice C/A Ratio
Not Available   
Not Available   

Mechanical Properties

Density
  
  

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

Density When Liquid (at m.p.)
1.46 g/cm3   
99+
1.84 g/cm3   
99+

Tensile Strength
Not Available   
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Elasticity properties
  
  

Bulk Modulus
2.50 GPa   
99+
1.60 GPa   
99+

Young's Modulus
2.40 GPa   
99+
1.70 GPa   
99+

Poisson Ratio
Not Available   
Not Available   

Other Mechanical Properties
Ductile   
Ductile   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
1.53   
99+
1.87   
99+

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Semiconductor   

Resistivity
128.00 nΩ·m   
26
205.00 nΩ·m   
17

Electrical Conductivity
0.08 106/cm Ω   
24
0.05 106/cm Ω   
35

Electron Affinity
46.90 kJ/mol   
24
45.50 kJ/mol   
25

Thermal Properties

Specific Heat
0.36 J/(kg K)   
17
0.24 J/(kg K)   
23

Molar Heat Capacity
31.06 J/mol·K   
5
32.21 J/mol·K   
4

Thermal Conductivity
58.20 W/m·K   
26
35.90 W/m·K   
36

Critical Temperature
2,093.00 K   
4
1,938.00 K   
5

Thermal Expansion
90.00 µm/(m·K)   
2
97.00 µm/(m·K)   
1

Enthalpy
  
  

Enthalpy of Vaporization
69.20 kJ/mol   
99+
65.90 kJ/mol   
99+

Enthalpy of Fusion
2.19 kJ/mol   
99+
2.10 kJ/mol   
99+

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

Standard Molar Entropy
76.80 J/mol.K   
5
85.20 J/mol.K   
3

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