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Strontium Rubidium Comparison


Rubidium Strontium comparison


Periodic Table

Symbol
Sr   
Rb   

Group Number
2   
16
1   
17

Period Number
5   
5   

Block
s block   
s block   

Element Family
Alkaline Earth   
Alkali   

CAS Number
7440246   
99+
7440177   
99+

Space Group Name
Fm_ 3m   
Im_ 3m   

Space Group Number
225.00   
2
229.00   
1

Facts

Interesting Facts
  • Strontium element is softer than Calcium.
  • Silvery Strontium turns yellow, if exposed to air.
  
  • Rubidium metal is 16th most common element found in the earth crust.
  • Rubidium metal also found in minerals as well as seawater.
  

Sources
Found in Minerals, Mining, Ores of Minerals   
Obtained from Lithium Production.   

History
  
  

Who Discovered
William Cruickshank   
Robert Bunsen and Gustav Kirchhoff   

Discovery
In 1787   
In 1861   

Abundance
  
  

Abundance In Universe
4 * 10-6 %   
14
1 * 10-6 %   
16

Abundance In Sun
~0.000005 %   
15
~0.000003 %   
17

Abundance In Meteorites
0.00 %   
15
0.00 %   
19

Abundance In Earth's Crust
0.04 %   
10
0.01 %   
18

Abundance In Oceans
0.00 %   
4
0.00 %   
7

Abundance In Humans
0.00 %   
7
0.00 %   
7

Uses

Uses & Benefits
  • Strontium metal is used to producing ferrite magnets as well as refining zinc.
  • By-product of nuclear reactors called Strontium-90 is a radioactive isotope; it is absorbed by tissues and destroys bone marrow and cancer growth.
  
  • 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
Ammunition Industry, Chemical Industry   
NA   

Medical Uses
NA   
NA   

Other Uses
Alloys   
Alloys, Research Purposes   

Biological Properties
  
  

Toxicity
Non Toxic   
Non Toxic   

Present in Human Body
Yes   
Yes   

In Blood
0.03 Blood/mg dm-3   
19
2.49 Blood/mg dm-3   
7

In Bone
140.00 p.p.m.   
7
5.00 p.p.m.   
13

Physical Properties

Melting Point
769.00 °C   
99+
38.89 °C   
99+

Boiling Point
1,384.00 °C   
99+
688.00 °C   
99+

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silvery White   
Grayish White   

Luster
Metallic   
NA   

Hardness
  
  

Mohs Hardness
1.50   
18
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
Sr   
Rb   

Isotopes
  
  

Known Isotopes
27   
12
29   
10

Electronegativity
  
  

Pauling Electronegativity
0.95   
99+
0.82   
99+

Sanderson Electronegativity
0.72   
27
0.31   
32

Allred Rochow Electronegativity
0.99   
37
0.89   
40

Mulliken-Jaffe Electronegativity
1.00   
18
0.69   
24

Allen Electronegativity
0.96   
40
0.71   
99+

Electropositivity
  
  

Pauling Electropositivity
3.05   
7
3.18   
3

Ionization Energies
  
  

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

2nd Energy Level
1,064.20 kJ/mol   
99+
2,633.00 kJ/mol   
6

3rd Energy Level
4,138.00 kJ/mol   
10
3,860.00 kJ/mol   
11

4th Energy Level
5,500.00 kJ/mol   
13
5,080.00 kJ/mol   
18

5th Energy Level
6,910.00 kJ/mol   
18
6,850.00 kJ/mol   
19

6th Energy Level
8,760.00 kJ/mol   
18
8,140.00 kJ/mol   
20

7th Energy level
10,230.00 kJ/mol   
19
9,570.00 kJ/mol   
20

8th Energy Level
11,800.00 kJ/mol   
19
13,120.00 kJ/mol   
17

9th Energy Level
15,600.00 kJ/mol   
17
14,500.00 kJ/mol   
18

10th Energy Level
17,100.00 kJ/mol   
19
26,740.00 kJ/mol   
6

11th Energy Level
31,270.00 kJ/mol   
6
Not Available   

Electrochemical Equivalent
1.64 g/amp-hr   
99+
3.19 g/amp-hr   
14

Electron Work Function
2.59 eV   
99+
2.16 eV   
99+

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

Atomic Properties

Atomic Number
38   
99+
37   
99+

Electron Configuration
[Kr] 5s2   
[Kr] 5s1   

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

Crystal Lattice
FCC-Crystal-Structure-of-Strontium.jpg#100   
BCC-Crystal-Structure-.jpg#100   

Atom
  
  

Number of Protons
38   
99+
37   
99+

Number of Neutrons
50   
99+
48   
99+

Number of Electrons
38   
99+
37   
99+

Radius of an Atom
  
  

Atomic Radius
215.00 pm   
5
248.00 pm   
2

Covalent Radius
195.00 pm   
15
220.00 pm   
4

Van der Waals Radius
249.00 pm   
7
303.00 pm   
3

Atomic Weight
87.62 amu   
99+
85.47 amu   
99+

Atomic Volume
33.70 cm3/mol   
6
55.90 cm3/mol   
2

Adjacent Atomic Numbers
  
  

Previous Element
Rubidium
  
Gallium
  

Next Element
Yttrium
  
Strontium
  

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

Lattice Constant
608.49 pm   
6
558.50 pm   
10

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
2.64 g/cm3   
99+
1.53 g/cm3   
99+

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

Tensile Strength
Not Available   
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Vapor Pressure at 1000 K
121.00 (Pa)   
1
Not Available   

Elasticity properties
  
  

Shear Modulus
6.03 GPa   
99+
Not Available   

Bulk Modulus
Not Available   
2.50 GPa   
99+

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

Poisson Ratio
0.28   
17
Not Available   

Other Mechanical Properties
NA   
Ductile   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
2.64   
99+
1.53   
99+

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
NA   
Conductor   

Resistivity
132.00 nΩ·m   
24
128.00 nΩ·m   
26

Electrical Conductivity
0.08 106/cm Ω   
26
0.08 106/cm Ω   
24

Electron Affinity
5.03 kJ/mol   
38
46.90 kJ/mol   
24

Thermal Properties

Specific Heat
0.30 J/(kg K)   
18
0.36 J/(kg K)   
17

Molar Heat Capacity
26.40 J/mol·K   
28
31.06 J/mol·K   
5

Thermal Conductivity
35.40 W/m·K   
37
58.20 W/m·K   
26

Critical Temperature
Not Available   
2,093.00 K   
4

Thermal Expansion
22.50 µm/(m·K)   
18
90.00 µm/(m·K)   
2

Enthalpy
  
  

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

Enthalpy of Fusion
9.16 kJ/mol   
38
2.19 kJ/mol   
99+

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

Standard Molar Entropy
55.00 J/mol.K   
26
76.80 J/mol.K   
5

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