Symbol
Fm
Cs
Group Number
31
0
17
👆🏻
Period Number
76
2
7
👆🏻
Block
f block
s block
Element Family
Actinide
Alkali
CAS Number
74407247440462
7429905
54386242
👆🏻
Space Group Name
-
Im_ 3m
Space Group Number
194.00229.00
11
276
👆🏻
Interesting Facts
- Fermium metal is highly radioactive in nature.
- Fermium is synthetically produced metal.
Cesium is the most alkaline metal and is used in atomic clocks.
Sources
Bombarding Pu-239 with Neutrons
Earth's crust, Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
Lawrence Berkeley National Laboratory
Robert Bunsen and Gustav Kirchhoff
Discovery
In 1952
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
1.4
👆🏻
Uses & Benefits
- Currently known uses of Fermium metal are limited to research purpose only.
- 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
1,527.00 °C28.50 °C
-38.83
3410
👆🏻
Boiling Point
0.00 °C678.40 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
-
Silvery Gold
Luster
-
-
Hardness
Mohs Hardness
6.000.20
0.2
8.5
👆🏻
Brinell Hardness
500.00 MPa0.14 MPa
0.14
3490
👆🏻
Vickers Hardness
600.00 MPa0.14 MPa
0
3920
👆🏻
Speed of Sound
2,500.00 m/s1,630.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
1.301.93
0.155
3.41
👆🏻
Reflectivity
59.00 %35.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
-
-
β Allotropes
-
-
γ Allotropes
-
-
Chemical Formula
Fm
Cs
Isotopes
Known Isotopes
1836
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
1.300.66
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
2.703.21
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
627.00 kJ/mol375.70 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
1,225.00 kJ/mol2,234.30 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
2,363.00 kJ/mol3,400.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
3,792.00 kJ/mol375.70 kJ/mol
375.7
37066
👆🏻
5th Energy Level
6,270.00 kJ/mol3,750.00 kJ/mol
392
97510
👆🏻
6th Energy Level
6,270.00 kJ/mol3,750.00 kJ/mol
1007
105800
👆🏻
7th Energy level
6,270.00 kJ/mol3,750.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
6,270.00 kJ/mol3,760.00 kJ/mol
730
125300
👆🏻
9th Energy Level
7,040.00 kJ/mol3,750.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
6,270.00 kJ/mol3,757.00 kJ/mol
392
144300
👆🏻
11th Energy Level
6,270.00 kJ/mol3,757.00 kJ/mol
392
169988
👆🏻
12th Energy Level
62,700.00 kJ/mol3,750.00 kJ/mol
0
189368
👆🏻
13th Energy Level
6,270.00 kJ/mol3,750.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
6,270.00 kJ/mol3,750.00 kJ/mol
380
86450
👆🏻
15th Energy Level
62,700.00 kJ/mol37,500.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
62,700.00 kJ/mol375.70 kJ/mol
375.7
109480
👆🏻
17th Energy Level
627.00 kJ/mol375.70 kJ/mol
375.7
122200
👆🏻
18th Energy Level
6,270.00 kJ/mol3,757.00 kJ/mol
0
134810
👆🏻
19th Energy Level
994.80 kJ/mol375.70 kJ/mol
375.7
148700
👆🏻
20th Energy Level
627.00 kJ/mol375.00 kJ/mol
0
171200
👆🏻
21st Energy Level
627.00 kJ/mol375.70 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
345.00 kJ/mol375.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
6,270.00 kJ/mol375.70 kJ/mol
357.6
198800
👆🏻
24th Energy Level
627.60 kJ/mol375.70 kJ/mol
297.3
195200
👆🏻
25th Energy Level
627.00 kJ/mol375.70 kJ/mol
0
121900
👆🏻
26th Energy Level
627.60 kJ/mol375.70 kJ/mol
357.6
127700
👆🏻
27th Energy Level
627.60 kJ/mol375.70 kJ/mol
0
133800
👆🏻
28th Energy Level
627.60 kJ/mol375.70 kJ/mol
297.3
139800
👆🏻
29th Energy Level
627.60 kJ/mol375.70 kJ/mol
0
148100
👆🏻
30th Energy Level
627.60 kJ/mol375.70 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
3.20 g/amp-hr4.96 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
4.47 eV2.14 eV
2.14
6
👆🏻
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
Chemical Stability, Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Number
10055
3
117
👆🏻
Electron Configuration
[Rn] 5f12 7s2
[Xe] 6s1
Crystal Structure
Not Known
Body Centered Cubic (BCC)
Crystal Lattice
Atom
Number of Protons
10055
3
117
👆🏻
Number of Neutrons
15778
4
285
👆🏻
Number of Electrons
10055
3
117
👆🏻
Radius of an Atom
Atomic Radius
180.00 pm265.00 pm
0
348
👆🏻
Covalent Radius
180.00 pm244.00 pm
0
260
👆🏻
Van der Waals Radius
245.00 pm343.00 pm
0
348
👆🏻
Atomic Weight
257.00 amu132.91 amu
6.94
294
👆🏻
Atomic Volume
18.00 cm3/mol71.07 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
0.00 (-eV)8.62 (-eV)
0
392.42
👆🏻
Lattice Constant
350.00 pm614.10 pm
0
891.25
👆🏻
Lattice Angles
-
π/2, π/2, π/2
Lattice C/A Ratio
1.631.87
0.423
1.9
👆🏻
Density
Density At Room Temperature
9.70 g/cm31.93 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
9.70 g/cm31.84 g/cm3
0.512
41
👆🏻
Tensile Strength
0.10 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
30.00 GPa30.00 GPa
1.3
222
👆🏻
Bulk Modulus
50.00 GPa1.60 GPa
0
462
👆🏻
Young's Modulus
0.00 GPa1.70 GPa
0
528
👆🏻
Poisson Ratio
0.350.35
0.032
0.47
👆🏻
Other Mechanical Properties
-
Ductile
Magnetic Characteristics
Specific Gravity
9.701.87
0.53
4500
👆🏻
Magnetic Ordering
-
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
Resistivity
7.90 nΩ·m205.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.00 106/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
0.00 W/m·K35.90 W/m·K
0
429
👆🏻
Critical Temperature
1,323.00 K1,938.00 K
26.3
3695
👆🏻
Thermal Expansion
11.00 µm/(m·K)97.00 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
319.20 kJ/mol65.90 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
13.30 kJ/mol2.10 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
-78.20 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
50.00 J/mol.K85.20 J/mol.K
9.5
198.1
👆🏻