Symbol
Be
Cs
Group Number
21
0
17
👆🏻
Period Number
26
2
7
👆🏻
Block
s block
s block
Element Family
Alkaline Earth
Alkali
CAS Number
74404177440462
7429905
54386242
👆🏻
Space Group Name
P63/mmc
Im_ 3m
Space Group Number
194.00229.00
11
276
👆🏻
Interesting Facts
- Beryllium is best anti corrosion metal.
- Beryllium is the lightest metal and still it is stronger than steel.
- It also finds various applications in Nuclear reactors as a reflector.
Cesium is the most alkaline metal and is used in atomic clocks.
Sources
Earth's crust, Found in Minerals, Mining, Ores of metals, Ores of Minerals
Earth's crust, Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
Louis Nicolas Vauquelin
Robert Bunsen and Gustav Kirchhoff
Discovery
In 1797
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 %0.00 %
0
1.1
👆🏻
Abundance In Humans
0.00 %0.00 %
0
1.4
👆🏻
Uses & Benefits
- Its alloys with copper or nickel are used in manufacturing Gyroscopes, springs, electrical contact and non sparking tools.
- Beryllium Alloys are used as a material for aircraft, missiles, spacecraft and satellite.
- 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, Ammunition Industry, Automobile Industry, Electrical Industry, Electronic Industry
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Medical Uses
-
-
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Toxic
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
1,278.00 °C28.50 °C
-38.83
3410
👆🏻
Boiling Point
2,970.00 °C678.40 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
White Gray
Silvery Gold
Luster
Metallic
-
Hardness
Mohs Hardness
5.500.20
0.2
8.5
👆🏻
Brinell Hardness
590.00 MPa0.14 MPa
0.14
3490
👆🏻
Vickers Hardness
1,670.00 MPa0.14 MPa
0
3920
👆🏻
Speed of Sound
12,890.00 m/s1,630.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
1.561.93
0.155
3.41
👆🏻
Reflectivity
65.00 %35.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
-
-
β Allotropes
-
-
γ Allotropes
-
-
Chemical Formula
Be
Cs
Isotopes
Known Isotopes
936
0
38
👆🏻
Electronegativity
Pauling Electronegativity
1.570.79
0
2.6
👆🏻
Sanderson Electronegativity
1.810.22
0.22
2.56
👆🏻
Allred Rochow Electronegativity
1.470.86
0.86
1.9
👆🏻
Mulliken-Jaffe Electronegativity
1.540.62
0.62
2.48
👆🏻
Allen Electronegativity
1.580.66
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
2.433.21
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
899.50 kJ/mol375.70 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
1,757.10 kJ/mol2,234.30 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
14,848.70 kJ/mol3,400.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
21,006.60 kJ/mol375.70 kJ/mol
375.7
37066
👆🏻
5th Energy Level
2,970.00 kJ/mol3,750.00 kJ/mol
392
97510
👆🏻
6th Energy Level
1,470.00 kJ/mol3,750.00 kJ/mol
1007
105800
👆🏻
7th Energy level
2,970.00 kJ/mol3,750.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
2,970.00 kJ/mol3,760.00 kJ/mol
730
125300
👆🏻
9th Energy Level
2,970.00 kJ/mol3,750.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
2,970.00 kJ/mol3,757.00 kJ/mol
392
144300
👆🏻
11th Energy Level
2,970.00 kJ/mol3,757.00 kJ/mol
392
169988
👆🏻
12th Energy Level
29,700.00 kJ/mol3,750.00 kJ/mol
0
189368
👆🏻
13th Energy Level
2,970.00 kJ/mol3,750.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
2,970.00 kJ/mol3,750.00 kJ/mol
380
86450
👆🏻
15th Energy Level
89,900.00 kJ/mol37,500.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
89,900.00 kJ/mol375.70 kJ/mol
375.7
109480
👆🏻
17th Energy Level
2,970.00 kJ/mol375.70 kJ/mol
375.7
122200
👆🏻
18th Energy Level
8,995.00 kJ/mol3,757.00 kJ/mol
0
134810
👆🏻
19th Energy Level
899.50 kJ/mol375.70 kJ/mol
375.7
148700
👆🏻
20th Energy Level
899.00 kJ/mol375.00 kJ/mol
0
171200
👆🏻
21st Energy Level
2,970.00 kJ/mol375.70 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
899.00 kJ/mol375.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
2,970.00 kJ/mol375.70 kJ/mol
357.6
198800
👆🏻
24th Energy Level
297.30 kJ/mol375.70 kJ/mol
297.3
195200
👆🏻
25th Energy Level
2,970.00 kJ/mol375.70 kJ/mol
0
121900
👆🏻
26th Energy Level
2,970.00 kJ/mol375.70 kJ/mol
357.6
127700
👆🏻
27th Energy Level
297.30 kJ/mol375.70 kJ/mol
0
133800
👆🏻
28th Energy Level
297.30 kJ/mol375.70 kJ/mol
297.3
139800
👆🏻
29th Energy Level
2,970.00 kJ/mol375.70 kJ/mol
0
148100
👆🏻
30th Energy Level
2,970.00 kJ/mol375.70 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
0.17 g/amp-hr4.96 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
4.98 eV2.14 eV
2.14
6
👆🏻
Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes
Chemical Stability, Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Number
455
3
117
👆🏻
Electron Configuration
[He] 2s2
[Xe] 6s1
Crystal Structure
Hexagonal Close Packed (HCP)
Body Centered Cubic (BCC)
Crystal Lattice
Atom
Number of Protons
455
3
117
👆🏻
Number of Neutrons
578
4
285
👆🏻
Number of Electrons
455
3
117
👆🏻
Radius of an Atom
Atomic Radius
112.00 pm265.00 pm
0
348
👆🏻
Covalent Radius
96.00 pm244.00 pm
0
260
👆🏻
Van der Waals Radius
153.00 pm343.00 pm
0
348
👆🏻
Atomic Weight
9.01 amu132.91 amu
6.94
294
👆🏻
Atomic Volume
5.00 cm3/mol71.07 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
82.00 (-eV)8.62 (-eV)
0
392.42
👆🏻
Lattice Constant
228.58 pm614.10 pm
0
891.25
👆🏻
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
1.571.87
0.423
1.9
👆🏻
Density
Density At Room Temperature
1.85 g/cm31.93 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
1.69 g/cm31.84 g/cm3
0.512
41
👆🏻
Tensile Strength
287.00 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
132.00 GPa30.00 GPa
1.3
222
👆🏻
Bulk Modulus
130.00 GPa1.60 GPa
0
462
👆🏻
Young's Modulus
287.00 GPa1.70 GPa
0
528
👆🏻
Poisson Ratio
0.030.35
0.032
0.47
👆🏻
Other Mechanical Properties
-
Ductile
Magnetic Characteristics
Specific Gravity
1.851.87
0.53
4500
👆🏻
Magnetic Ordering
Diamagnetic
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
Semiconductor
Resistivity
36.00 nΩ·m205.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.31 106/cm Ω0.05 106/cm Ω
0
0.63
👆🏻
Electron Affinity
0.00 kJ/mol45.50 kJ/mol
0
222.8
👆🏻
Specific Heat
1.82 J/(kg K)0.24 J/(kg K)
0.1
3.6
👆🏻
Molar Heat Capacity
16.44 J/mol·K32.21 J/mol·K
13.1
62.7
👆🏻
Thermal Conductivity
200.00 W/m·K35.90 W/m·K
0
429
👆🏻
Critical Temperature
1,551.00 K1,938.00 K
26.3
3695
👆🏻
Thermal Expansion
11.30 µm/(m·K)97.00 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
294.70 kJ/mol65.90 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
11.72 kJ/mol2.10 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
326.40 kJ/mol78.20 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
9.50 J/mol.K85.20 J/mol.K
9.5
198.1
👆🏻