Symbol
Cs
Rb
Group Number
11
0
17
👆🏻
Period Number
65
2
7
👆🏻
Block
s block
s block
Element Family
Alkali
Alkali
CAS Number
74404627440177
7429905
54386242
👆🏻
Space Group Name
Im_ 3m
Im_ 3m
Space Group Number
229.00229.00
11
276
👆🏻
Interesting Facts
Cesium is the most alkaline metal and is used in atomic clocks.
- Rubidium metal is 16th most common element found in the earth crust.
- Rubidium metal also found in minerals as well as seawater.
Sources
Earth's crust, Found in Minerals, Mining, Ores of Minerals
Obtained from Lithium Production.
History
Who Discovered
Robert Bunsen and Gustav Kirchhoff
Robert Bunsen and Gustav Kirchhoff
Discovery
In 1860
In 1861
Abundance
Abundance In Universe
0.00 %0.00 %
0
0.11
👆🏻
Abundance In Sun
0.00 %0.00 %
0
0.1
👆🏻
Abundance In Meteorites
0.00 %0.00 %
0
22
👆🏻
Abundance In Earth's Crust
0.00 %0.01 %
1E-37
8.1
👆🏻
Abundance In Oceans
0.00 %0.00 %
0
1.1
👆🏻
Abundance In Humans
0.00 %0.00 %
0
1.4
👆🏻
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.
- 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
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
-
Medical Uses
-
-
Other Uses
Alloys
Alloys, Research Purposes
Biological Properties
Toxicity
Mildly Toxic
Non Toxic
Present in Human Body
✔
✘
✔
✘
In Blood
0.00 Blood/mg dm-32.49 Blood/mg dm-3
0
1970
👆🏻
In Bone
0.05 p.p.m.5.00 p.p.m.
0
170000
👆🏻
Melting Point
28.50 °C38.89 °C
-38.83
3410
👆🏻
Boiling Point
678.40 °C688.00 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
Silvery Gold
Grayish White
Luster
-
-
Hardness
Mohs Hardness
0.200.30
0.2
8.5
👆🏻
Brinell Hardness
0.14 MPa0.22 MPa
0.14
3490
👆🏻
Vickers Hardness
0.14 MPa0.22 MPa
0
3920
👆🏻
Speed of Sound
1,630.00 m/s1,300.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
1.931.54
0.155
3.41
👆🏻
Reflectivity
35.00 %52.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
-
-
β Allotropes
-
-
γ Allotropes
-
-
Chemical Formula
Cs
Rb
Isotopes
Known Isotopes
3629
0
38
👆🏻
Electronegativity
Pauling Electronegativity
0.790.82
0
2.6
👆🏻
Sanderson Electronegativity
0.220.31
0.22
2.56
👆🏻
Allred Rochow Electronegativity
0.860.89
0.86
1.9
👆🏻
Mulliken-Jaffe Electronegativity
0.620.69
0.62
2.48
👆🏻
Allen Electronegativity
0.660.71
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
3.213.18
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
375.70 kJ/mol403.00 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
2,234.30 kJ/mol2,633.00 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
3,400.00 kJ/mol3,860.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
375.70 kJ/mol5,080.00 kJ/mol
375.7
37066
👆🏻
5th Energy Level
3,750.00 kJ/mol6,850.00 kJ/mol
392
97510
👆🏻
6th Energy Level
3,750.00 kJ/mol8,140.00 kJ/mol
1007
105800
👆🏻
7th Energy level
3,750.00 kJ/mol9,570.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
3,760.00 kJ/mol13,120.00 kJ/mol
730
125300
👆🏻
9th Energy Level
3,750.00 kJ/mol14,500.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
3,757.00 kJ/mol26,740.00 kJ/mol
392
144300
👆🏻
11th Energy Level
3,757.00 kJ/mol4,030.00 kJ/mol
392
169988
👆🏻
12th Energy Level
3,750.00 kJ/mol4,030.00 kJ/mol
0
189368
👆🏻
13th Energy Level
3,750.00 kJ/mol4,030.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
3,750.00 kJ/mol4,030.00 kJ/mol
380
86450
👆🏻
15th Energy Level
37,500.00 kJ/mol40,300.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
375.70 kJ/mol40,300.00 kJ/mol
375.7
109480
👆🏻
17th Energy Level
375.70 kJ/mol403.00 kJ/mol
375.7
122200
👆🏻
18th Energy Level
3,757.00 kJ/mol4,030.00 kJ/mol
0
134810
👆🏻
19th Energy Level
375.70 kJ/mol403.00 kJ/mol
375.7
148700
👆🏻
20th Energy Level
375.00 kJ/mol403.00 kJ/mol
0
171200
👆🏻
21st Energy Level
375.70 kJ/mol403.00 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
375.00 kJ/mol403.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
375.70 kJ/mol403.00 kJ/mol
357.6
198800
👆🏻
24th Energy Level
375.70 kJ/mol403.00 kJ/mol
297.3
195200
👆🏻
25th Energy Level
375.70 kJ/mol403.00 kJ/mol
0
121900
👆🏻
26th Energy Level
375.70 kJ/mol403.00 kJ/mol
357.6
127700
👆🏻
27th Energy Level
375.70 kJ/mol403.00 kJ/mol
0
133800
👆🏻
28th Energy Level
375.70 kJ/mol403.00 kJ/mol
297.3
139800
👆🏻
29th Energy Level
375.70 kJ/mol403.00 kJ/mol
0
148100
👆🏻
30th Energy Level
375.70 kJ/mol403.00 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
4.96 g/amp-hr3.19 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
2.14 eV2.16 eV
2.14
6
👆🏻
Other Chemical Properties
Chemical Stability, Corrosion, Ionization, Radioactive Isotopes, Solubility
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
Atomic Number
5537
3
117
👆🏻
Electron Configuration
[Xe] 6s1
[Kr] 5s1
Crystal Structure
Body Centered Cubic (BCC)
Body Centered Cubic (BCC)
Crystal Lattice
Atom
Number of Protons
5537
3
117
👆🏻
Number of Neutrons
7848
4
285
👆🏻
Number of Electrons
5537
3
117
👆🏻
Radius of an Atom
Atomic Radius
265.00 pm248.00 pm
0
348
👆🏻
Covalent Radius
244.00 pm220.00 pm
0
260
👆🏻
Van der Waals Radius
343.00 pm303.00 pm
0
348
👆🏻
Atomic Weight
132.91 amu85.47 amu
6.94
294
👆🏻
Atomic Volume
71.07 cm3/mol55.90 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
8.62 (-eV)9.47 (-eV)
0
392.42
👆🏻
Lattice Constant
614.10 pm558.50 pm
0
891.25
👆🏻
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
1.871.59
0.423
1.9
👆🏻
Density
Density At Room Temperature
1.93 g/cm31.53 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
1.84 g/cm31.46 g/cm3
0.512
41
👆🏻
Tensile Strength
15.00 MPa30.00 MPa
0.1
11000
👆🏻
Viscosity
0.000.00
1.5E-05
0.0035
👆🏻
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)0.00 (Pa)
0
121
👆🏻
Vapor Pressure at 2000 K
0.00 (Pa)0.00 (Pa)
0
774
👆🏻
Elasticity properties
Shear Modulus
30.00 GPa2.50 GPa
1.3
222
👆🏻
Bulk Modulus
1.60 GPa2.50 GPa
0
462
👆🏻
Young's Modulus
1.70 GPa2.40 GPa
0
528
👆🏻
Poisson Ratio
0.350.37
0.032
0.47
👆🏻
Other Mechanical Properties
Ductile
Ductile
Magnetic Characteristics
Specific Gravity
1.871.53
0.53
4500
👆🏻
Magnetic Ordering
Paramagnetic
Paramagnetic
Permeability
0.00 H/m0.00 H/m
1.25643E-06
0.0063
👆🏻
Susceptibility
0.000.00
-0.000166
200000
👆🏻
Electrical Properties
Electrical Property
Semiconductor
Conductor
Resistivity
205.00 nΩ·m128.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.05 106/cm Ω0.08 106/cm Ω
0
0.63
👆🏻
Electron Affinity
45.50 kJ/mol46.90 kJ/mol
0
222.8
👆🏻
Specific Heat
0.24 J/(kg K)0.36 J/(kg K)
0.1
3.6
👆🏻
Molar Heat Capacity
32.21 J/mol·K31.06 J/mol·K
13.1
62.7
👆🏻
Thermal Conductivity
35.90 W/m·K58.20 W/m·K
0
429
👆🏻
Critical Temperature
1,938.00 K2,093.00 K
26.3
3695
👆🏻
Thermal Expansion
97.00 µm/(m·K)90.00 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
65.90 kJ/mol69.20 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
2.10 kJ/mol2.19 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
78.20 kJ/mol82.00 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
85.20 J/mol.K76.80 J/mol.K
9.5
198.1
👆🏻