Symbol
Bk
Cs
Group Number
141
0
17
👆🏻
Period Number
76
2
7
👆🏻
Block
f block
s block
Element Family
Actinide
Alkali
CAS Number
74404067440462
7429905
54386242
👆🏻
Space Group Name
P63/mmc
Im_ 3m
Space Group Number
194.00229.00
11
276
👆🏻
Interesting Facts
- X-ray Diffraction- different compounds of Berkelium metals are identified using it.
Commercial uses of Berkelium metal are not yet discovered.
Cesium is the most alkaline metal and is used in atomic clocks.
Sources
Bombarding Americium with Alpha Particles.
Earth's crust, Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
Lawrence Berkeley National Laboratory
Robert Bunsen and Gustav Kirchhoff
Discovery
In 1949
In 1860
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 %0.00 %
1E-37
8.1
👆🏻
Abundance In Oceans
-0.00 %
0
1.1
👆🏻
Abundance In Humans
0.00 %0.00 %
0
1.4
👆🏻
Uses & Benefits
- This metal is very rare and has no commercial uses.
- 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
-
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Medical Uses
-
-
Other Uses
-
Alloys
Biological Properties
Toxicity
-
Mildly Toxic
Present in Human Body
✔
✘
✔
✘
In Blood
0.00 Blood/mg dm-30.00 Blood/mg dm-3
0
1970
👆🏻
In Bone
0.00 p.p.m.0.05 p.p.m.
0
170000
👆🏻
Melting Point
986.00 °C28.50 °C
-38.83
3410
👆🏻
Boiling Point
2,627.00 °C678.40 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
Silver
Silvery Gold
Luster
Metallic
-
Hardness
Mohs Hardness
6.000.20
0.2
8.5
👆🏻
Brinell Hardness
260.00 MPa0.14 MPa
0.14
3490
👆🏻
Vickers Hardness
1,070.00 MPa0.14 MPa
0
3920
👆🏻
Speed of Sound
2,560.00 m/s1,630.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
1.301.93
0.155
3.41
👆🏻
Reflectivity
61.00 %35.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
-
-
β Allotropes
-
-
γ Allotropes
-
-
Chemical Formula
Bk
Cs
Isotopes
Known Isotopes
1436
0
38
👆🏻
Electronegativity
Pauling Electronegativity
1.300.79
0
2.6
👆🏻
Sanderson Electronegativity
1.300.22
0.22
2.56
👆🏻
Allred Rochow Electronegativity
1.200.86
0.86
1.9
👆🏻
Mulliken-Jaffe Electronegativity
1.300.62
0.62
2.48
👆🏻
Allen Electronegativity
2.700.66
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
2.703.21
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
601.00 kJ/mol375.70 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
1,186.00 kJ/mol2,234.30 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
2,152.00 kJ/mol3,400.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
3,434.00 kJ/mol375.70 kJ/mol
375.7
37066
👆🏻
5th Energy Level
6,010.00 kJ/mol3,750.00 kJ/mol
392
97510
👆🏻
6th Energy Level
6,010.00 kJ/mol3,750.00 kJ/mol
1007
105800
👆🏻
7th Energy level
6,010.00 kJ/mol3,750.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
6,010.00 kJ/mol3,760.00 kJ/mol
730
125300
👆🏻
9th Energy Level
6,010.00 kJ/mol3,750.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
6,010.00 kJ/mol3,757.00 kJ/mol
392
144300
👆🏻
11th Energy Level
6,010.00 kJ/mol3,757.00 kJ/mol
392
169988
👆🏻
12th Energy Level
60,100.00 kJ/mol3,750.00 kJ/mol
0
189368
👆🏻
13th Energy Level
6,010.00 kJ/mol3,750.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
6,010.00 kJ/mol3,750.00 kJ/mol
380
86450
👆🏻
15th Energy Level
60,100.00 kJ/mol37,500.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
60,100.00 kJ/mol375.70 kJ/mol
375.7
109480
👆🏻
17th Energy Level
601.00 kJ/mol375.70 kJ/mol
375.7
122200
👆🏻
18th Energy Level
6,010.00 kJ/mol3,757.00 kJ/mol
0
134810
👆🏻
19th Energy Level
601.00 kJ/mol375.70 kJ/mol
375.7
148700
👆🏻
20th Energy Level
601.00 kJ/mol375.00 kJ/mol
0
171200
👆🏻
21st Energy Level
6,010.00 kJ/mol375.70 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
601.00 kJ/mol375.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
6,010.00 kJ/mol375.70 kJ/mol
357.6
198800
👆🏻
24th Energy Level
601.00 kJ/mol375.70 kJ/mol
297.3
195200
👆🏻
25th Energy Level
601.00 kJ/mol375.70 kJ/mol
0
121900
👆🏻
26th Energy Level
601.00 kJ/mol375.70 kJ/mol
357.6
127700
👆🏻
27th Energy Level
601.00 kJ/mol375.70 kJ/mol
0
133800
👆🏻
28th Energy Level
601.00 kJ/mol375.70 kJ/mol
297.3
139800
👆🏻
29th Energy Level
601.00 kJ/mol375.70 kJ/mol
0
148100
👆🏻
30th Energy Level
601.00 kJ/mol375.70 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
3.07 g/amp-hr4.96 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
4.90 eV2.14 eV
2.14
6
👆🏻
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
Chemical Stability, Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Number
9755
3
117
👆🏻
Electron Configuration
[Rn] 5f9 7s2
[Xe] 6s1
Crystal Structure
Double Hexagonal Close Packed (DHCP)
Body Centered Cubic (BCC)
Crystal Lattice
Atom
Number of Protons
9755
3
117
👆🏻
Number of Neutrons
15078
4
285
👆🏻
Number of Electrons
9755
3
117
👆🏻
Radius of an Atom
Atomic Radius
170.00 pm265.00 pm
0
348
👆🏻
Covalent Radius
170.00 pm244.00 pm
0
260
👆🏻
Van der Waals Radius
244.00 pm343.00 pm
0
348
👆🏻
Atomic Weight
247.00 amu132.91 amu
6.94
294
👆🏻
Atomic Volume
13.39 cm3/mol71.07 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
45.50 (-eV)8.62 (-eV)
0
392.42
👆🏻
Lattice Constant
341.60 pm614.10 pm
0
891.25
👆🏻
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.571.87
0.423
1.9
👆🏻
Density
Density At Room Temperature
14.78 g/cm31.93 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
13.25 g/cm31.84 g/cm3
0.512
41
👆🏻
Tensile Strength
70.00 MPa15.00 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
27.00 GPa30.00 GPa
1.3
222
👆🏻
Bulk Modulus
13.00 GPa1.60 GPa
0
462
👆🏻
Young's Modulus
13.00 GPa1.70 GPa
0
528
👆🏻
Poisson Ratio
0.350.35
0.032
0.47
👆🏻
Other Mechanical Properties
-
Ductile
Magnetic Characteristics
Specific Gravity
14.001.87
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
Conductor
Semiconductor
Resistivity
7.60 nΩ·m205.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.10 106/cm Ω0.05 106/cm Ω
0
0.63
👆🏻
Electron Affinity
0.00 kJ/mol45.50 kJ/mol
0
222.8
👆🏻
Specific Heat
0.10 J/(kg K)0.24 J/(kg K)
0.1
3.6
👆🏻
Molar Heat Capacity
27.00 J/mol·K32.21 J/mol·K
13.1
62.7
👆🏻
Thermal Conductivity
10.00 W/m·K35.90 W/m·K
0
429
👆🏻
Critical Temperature
1,323.00 K1,938.00 K
26.3
3695
👆🏻
Thermal Expansion
13.25 µm/(m·K)97.00 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
380.00 kJ/mol65.90 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
13.25 kJ/mol2.10 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
601.00 kJ/mol78.20 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
52.00 J/mol.K85.20 J/mol.K
9.5
198.1
👆🏻