Thulium vs Cerium
Periodic Table
Symbol
Tm
Ce
Group Number
Not Available
Not Available
Period Number
6
6
Block
f block
f block
Element Family
Lanthanide
Lanthanide
CAS Number
7440304
99+
7440451
99+
Space Group Name
P63/mmc
P63/mmc
Space Group Number
194.00
5
194.00
5
Facts
Interesting Facts
- Thulium metal can resist corrosion due to dry air .
- Only Tm-169 isotope of Thulium metal occur naturally.
- Cerium is a rare earth metal but still it is not rare at all.
- It’s non-toxic compound Cerium sulfide has a rich red color and it is used as a pigment.
- Cerium metal is also used in Flat screen TVs, light bulb, floodlights, etc.
Sources
Found in Minerals, Mining, Ores of Minerals
Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
Per Teodor Cleve
Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
Discovery
In 1879
In 1803
Abundance
Abundance In Universe
1 * 10-8 %
30
1 * 10-6 %
16
Abundance In Sun
~0.00000002 %
28
~0.0000004 %
23
Abundance In Meteorites
0.00 %
99+
0.00 %
27
Abundance In Earth's Crust
0.00 %
99+
0.01 %
18
Abundance In Oceans
0.00 %
99+
0.00 %
33
Uses
Uses & Benefits
- Thulium metal produces isotopes that emits X-rays. This isotope is used in X-ray machine.
- Thulium element is also used in Surgical equipment like laser.
- It is used to include flints for cigarette lighters.
- Its compound Cerium (Ill) Oxide is used as a catalyst; it is put inside the walls of the oven as it prevents from the buildup of cooking residues.
Industrial Uses
NA
Chemical Industry
Medical Uses
NA
Medical Research
Other Uses
Alloys, Nuclear Research, Research Purposes
Alloys
Biological Properties
Toxicity
Unknown
Moderately Toxic
Present in Human Body
No
Yes
In Blood
Not Available
0.00 Blood/mg dm-3
30
In Bone
Not Available
2.70 p.p.m.
14
Physical Properties
Melting Point
1,545.00 °C
23
795.00 °C
99+
Boiling Point
1,730.00 °C
99+
3,257.00 °C
23
Appearance
Physical State
Solid
Solid
Color
Silvery Gray
Silvery White
Luster
Metallic
Lustrous
Hardness
Mohs Hardness
Not Available
2.50
14
Brinell Hardness
471.00 MPa
25
186.00 MPa
99+
Vickers Hardness
520.00 MPa
21
210.00 MPa
32
Speed of Sound
Not Available
2,100.00 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
Tm
Ce
Isotopes
Known Isotopes
32
7
30
9
Electronegativity
Pauling Electronegativity
1.25
35
1.12
99+
Allred Rochow Electronegativity
1.11
29
1.08
31
Electropositivity
Pauling Electropositivity
2.75
19
2.88
11
Ionization Energies
1st Energy Level
596.70 kJ/mol
99+
534.40 kJ/mol
99+
2nd Energy Level
1,160.00 kJ/mol
99+
1,050.00 kJ/mol
99+
3rd Energy Level
2,285.00 kJ/mol
99+
1,949.00 kJ/mol
99+
4th Energy Level
4,120.00 kJ/mol
33
3,547.00 kJ/mol
99+
5th Energy Level
Not Available
6,325.00 kJ/mol
22
6th Energy Level
Not Available
7,490.00 kJ/mol
21
Electrochemical Equivalent
2.10 g/amp-hr
26
1.74 g/amp-hr
99+
Electron Work Function
Not Available
2.84 eV
39
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
69
99+
58
99+
Electron Configuration
[Xe] 4f13 6s2
[Xe] 4f1 5d1 6s2
Crystal Structure
Hexagonal Close Packed (HCP)
Double Hexagonal Close Packed (DHCP)
Crystal Lattice
HCP-Crystal-Structure-of-Thulium.jpg#100
DHCP-Crystal-Structure-of-Cerium.jpg#100
Atom
Number of Protons
69
99+
58
99+
Number of Neutrons
100
32
82
99+
Number of Electrons
69
99+
58
99+
Radius of an Atom
Atomic Radius
176.00 pm
18
181.80 pm
12
Covalent Radius
160.00 pm
30
204.00 pm
8
Van der Waals Radius
Not Available
235.00 pm
17
Atomic Weight
168.93 amu
99+
140.12 amu
99+
Atomic Volume
18.10 cm3/mol
28
20.67 cm3/mol
17
Adjacent Atomic Numbers
Valence Electron Potential
49.70 (-eV)
28
41.78 (-eV)
99+
Lattice Constant
353.75 pm
40
362.00 pm
34
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, 2 π/3
Lattice C/A Ratio
1.57
17
Not Available
Mechanical Properties
Density
Density At Room Temperature
9.32 g/cm3
40
6.77 g/cm3
99+
Density When Liquid (at m.p.)
8.56 g/cm3
24
6.55 g/cm3
38
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.06 (Pa)
10
0.00 (Pa)
34
Vapor Pressure at 2000 K
Not Available
1.04 (Pa)
13
Elasticity properties
Shear Modulus
30.50 GPa
22
13.50 GPa
99+
Bulk Modulus
44.50 GPa
26
21.50 GPa
99+
Young's Modulus
74.00 GPa
27
33.60 GPa
99+
Poisson Ratio
0.21
31
0.24
27
Other Mechanical Properties
Ductile, Malleable
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
9.32
31
6.77
99+
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
676.00 nΩ·m
5
828.00 nΩ·m
3
Electrical Conductivity
0.02 106/cm Ω
99+
0.01 106/cm Ω
99+
Electron Affinity
50.00 kJ/mol
21
50.00 kJ/mol
21
Thermal Properties
Specific Heat
0.16 J/(kg K)
35
0.19 J/(kg K)
32
Molar Heat Capacity
27.03 J/mol·K
22
26.94 J/mol·K
23
Thermal Conductivity
16.90 W/m·K
99+
11.30 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
13.30 µm/(m·K)
29
6.30 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
191.00 kJ/mol
99+
414.00 kJ/mol
16
Enthalpy of Fusion
16.80 kJ/mol
17
5.46 kJ/mol
99+
Enthalpy of Atomization
247.00 kJ/mol
99+
381.00 kJ/mol
23
Standard Molar Entropy
74.00 J/mol.K
9
72.00 J/mol.K
12
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