Holmium vs Cerium
Periodic Table
Symbol
Ho
Ce
Group Number
Not Available
Not Available
Period Number
6
6
Block
f block
f block
Element Family
Lanthanide
Lanthanide
CAS Number
7440600
29
7440451
99+
Space Group Name
P63/mmc
P63/mmc
Space Group Number
194.00
5
194.00
5
Facts
Interesting Facts
- Holmium metal is very soft and malleable.
- Holmium metal is well known for its corrosion resistivity.
- 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
Marc Delafontaine
Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
Discovery
In 1878
In 1803
Abundance
Abundance In Universe
5 * 10-8 %
27
1 * 10-6 %
16
Abundance In Sun
~-9999 %
~0.0000004 %
23
Abundance In Meteorites
0.00 %
99+
0.00 %
27
Abundance In Earth's Crust
0.00 %
38
0.01 %
18
Abundance In Oceans
0.00 %
99+
0.00 %
33
Uses
Uses & Benefits
- Holmium metal has an ability to absorb neutrons, so this metal is used in nuclear reactors to keep the chain reactions of elements under control.
- Alloys of Holmium are used to produce Magnet.
- 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
Alloys
Biological Properties
Toxicity
Low Toxic
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
1,461.00 °C
30
795.00 °C
99+
Boiling Point
2,600.00 °C
99+
3,257.00 °C
23
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silvery White
Luster
Metallic
Lustrous
Hardness
Mohs Hardness
Not Available
2.50
14
Brinell Hardness
746.00 MPa
13
186.00 MPa
99+
Vickers Hardness
481.00 MPa
23
210.00 MPa
32
Speed of Sound
2,760.00 m/s
30
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
Ho
Ce
Isotopes
Known Isotopes
34
5
30
9
Electronegativity
Pauling Electronegativity
1.23
37
1.12
99+
Allred Rochow Electronegativity
1.10
30
1.08
31
Electropositivity
Pauling Electropositivity
2.77
17
2.88
11
Ionization Energies
1st Energy Level
581.00 kJ/mol
99+
534.40 kJ/mol
99+
2nd Energy Level
1,140.00 kJ/mol
99+
1,050.00 kJ/mol
99+
3rd Energy Level
2,204.00 kJ/mol
99+
1,949.00 kJ/mol
99+
4th Energy Level
4,100.00 kJ/mol
34
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
2.02 g/amp-hr
29
1.74 g/amp-hr
99+
Electron Work Function
Not Available
2.84 eV
39
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
67
99+
58
99+
Electron Configuration
[Xe] 4f11 6s2
[Xe] 4f1 5d1 6s2
Crystal Structure
Hexagonal Close Packed (HCP)
Double Hexagonal Close Packed (DHCP)
Crystal Lattice
HCP-Crystal-Structure-of-Holmium.jpg#100
DHCP-Crystal-Structure-of-Cerium.jpg#100
Atom
Number of Protons
67
99+
58
99+
Number of Neutrons
98
34
82
99+
Number of Electrons
67
99+
58
99+
Radius of an Atom
Atomic Radius
176.00 pm
18
181.80 pm
12
Covalent Radius
192.00 pm
17
204.00 pm
8
Van der Waals Radius
216.00 pm
24
235.00 pm
17
Atomic Weight
164.93 amu
99+
140.12 amu
99+
Atomic Volume
18.70 cm3/mol
24
20.67 cm3/mol
17
Adjacent Atomic Numbers
Valence Electron Potential
47.90 (-eV)
31
41.78 (-eV)
99+
Lattice Constant
357.73 pm
38
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
8.79 g/cm3
99+
6.77 g/cm3
99+
Density When Liquid (at m.p.)
8.34 g/cm3
26
6.55 g/cm3
38
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
16
0.00 (Pa)
34
Vapor Pressure at 2000 K
Not Available
1.04 (Pa)
13
Elasticity properties
Shear Modulus
26.30 GPa
28
13.50 GPa
99+
Bulk Modulus
40.20 GPa
32
21.50 GPa
99+
Young's Modulus
64.80 GPa
31
33.60 GPa
99+
Poisson Ratio
0.23
29
0.24
27
Other Mechanical Properties
Ductile, Malleable, Sectile
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
8.80
35
6.77
99+
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
814.00 nΩ·m
4
828.00 nΩ·m
3
Electrical Conductivity
0.01 106/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
27.15 J/mol·K
19
26.94 J/mol·K
23
Thermal Conductivity
16.20 W/m·K
99+
11.30 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
11.20 µm/(m·K)
35
6.30 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
241.00 kJ/mol
38
414.00 kJ/mol
16
Enthalpy of Fusion
11.76 kJ/mol
29
5.46 kJ/mol
99+
Enthalpy of Atomization
301.00 kJ/mol
36
381.00 kJ/mol
23
Standard Molar Entropy
75.30 J/mol.K
8
72.00 J/mol.K
12
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