Holmium Actinium Comparison
Periodic Table
Symbol
Ho
Ac
Group Number
Not Available
Not Available
Period Number
6
7
Block
f block
f block
Element Family
Lanthanide
Actinide
CAS Number
7440600
29
7440348
99+
Space Group Name
P63/mmc
Fm_ 3m
Space Group Number
194.00
5
225.00
2
Facts
Interesting Facts
- Holmium metal is very soft and malleable.
- Holmium metal is well known for its corrosion resistivity.
Not Available
Sources
Found in Minerals, Mining, Ores of Minerals
Obtained by Treating Radium with Neutrons, Ores of metals
History
Who Discovered
Marc Delafontaine
Friedrich Oskar Giesel
Discovery
In 1878
In 1902
Abundance
Abundance In Universe
5 * 10-8 %
27
Not Available
Abundance In Meteorites
0.00 %
99+
Not Available
Abundance In Earth's Crust
0.00 %
38
Not Available
Abundance In Oceans
0.00 %
99+
Not Available
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.
- Actinium metal has a great source of alpha rays but it is hardly used outside research purpose.
Industrial Uses
NA
NA
Medical Uses
NA
NA
Other Uses
Alloys, Nuclear Research
Alloys, Nuclear Research, Research Purposes
Biological Properties
Toxicity
Low Toxic
Toxic
Present in Human Body
No
No
In Blood
Not Available
0.00 Blood/mg dm-3
37
In Bone
Not Available
0.00 p.p.m.
36
Physical Properties
Melting Point
1,461.00 °C
30
1,227.00 °C
38
Boiling Point
2,600.00 °C
99+
3,200.00 °C
26
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silvery White
Luster
Metallic
NA
Hardness
Brinell Hardness
746.00 MPa
13
Not Available
Vickers Hardness
481.00 MPa
23
Not Available
Speed of Sound
2,760.00 m/s
30
Not Available
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
Ac
Isotopes
Known Isotopes
34
5
29
10
Electronegativity
Pauling Electronegativity
1.23
37
1.10
99+
Allred Rochow Electronegativity
1.10
30
1.00
36
Electropositivity
Pauling Electropositivity
2.77
17
2.90
10
Ionization Energies
1st Energy Level
581.00 kJ/mol
99+
499.00 kJ/mol
99+
2nd Energy Level
1,140.00 kJ/mol
99+
1,170.00 kJ/mol
99+
3rd Energy Level
2,204.00 kJ/mol
99+
1,900.00 kJ/mol
99+
4th Energy Level
4,100.00 kJ/mol
34
4,700.00 kJ/mol
23
Electrochemical Equivalent
2.02 g/amp-hr
29
2.82 g/amp-hr
18
Electron Work Function
Not Available
Not Available
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Ionization, Radioactive Isotopes, Radioactivity, Solubility
Atomic Properties
Atomic Number
67
99+
89
29
Electron Configuration
[Xe] 4f11 6s2
[Rn] 6d1 7s2
Crystal Structure
Hexagonal Close Packed (HCP)
Face Centered Cubic (FCC)
Crystal Lattice
HCP-Crystal-Structure-of-Holmium.jpg#100
FCC-Crystal-Structure-of-Actinium.jpg#100
Atom
Number of Protons
67
99+
89
29
Number of Neutrons
98
34
138
16
Number of Electrons
67
99+
89
29
Radius of an Atom
Atomic Radius
176.00 pm
18
195.00 pm
7
Covalent Radius
192.00 pm
17
Not Available
Van der Waals Radius
216.00 pm
24
Not Available
Atomic Weight
164.93 amu
99+
227.00 amu
25
Atomic Volume
18.70 cm3/mol
24
22.54 cm3/mol
11
Adjacent Atomic Numbers
Valence Electron Potential
47.90 (-eV)
31
38.60 (-eV)
99+
Lattice Constant
357.73 pm
38
567.00 pm
8
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.57
17
Not Available
Mechanical Properties
Density
Density At Room Temperature
8.79 g/cm3
99+
10.00 g/cm3
37
Density When Liquid (at m.p.)
8.34 g/cm3
26
Not Available
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
16
Not Available
Elasticity properties
Shear Modulus
26.30 GPa
28
Not Available
Bulk Modulus
40.20 GPa
32
Not Available
Young's Modulus
64.80 GPa
31
Not Available
Poisson Ratio
0.23
29
Not Available
Other Mechanical Properties
Ductile, Malleable, Sectile
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
8.80
35
10.07
28
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Unknown
Resistivity
814.00 nΩ·m
4
Not Available
Electrical Conductivity
0.01 106/cm Ω
99+
Not Available
Electron Affinity
50.00 kJ/mol
21
Not Available
Thermal Properties
Specific Heat
0.16 J/(kg K)
35
0.12 J/(kg K)
40
Molar Heat Capacity
27.15 J/mol·K
19
27.20 J/mol·K
18
Thermal Conductivity
16.20 W/m·K
99+
12.00 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
11.20 µm/(m·K)
35
Not Available
Enthalpy
Enthalpy of Vaporization
241.00 kJ/mol
38
Not Available
Enthalpy of Fusion
11.76 kJ/mol
29
Not Available
Enthalpy of Atomization
301.00 kJ/mol
36
301.00 kJ/mol
36
Standard Molar Entropy
75.30 J/mol.K
8
56.50 J/mol.K
25
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