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Polonium vs Holmium

Polonium
Holmium
Holmium vs Polonium


Periodic Table
Symbol
Po   
Ho   
Group Number
16   
2
Not Available   
Period Number
6   
6   
Block
p block   
f block   
Element Family
Post-​Transition   
Lanthanide   
CAS Number
7440086   
99+
7440600   
29
Space Group Name
Pm-3m   
P63/mmc   
Space Group Number
221.00   
3
194.00   
5
Facts
Interesting Facts
  • Polonium was the first radioactive element to be discovered.
  • Polonium element and its compounds are highly radioactive.
  • Its alloy with Beryllium provides source of neutrons.
  
  • Holmium metal is very soft and malleable.
  • Holmium metal is well known for its corrosion resistivity.
  
Sources
Mining, Ores of metals   
Found in Minerals, Mining, Ores of Minerals   
History
  
  
Who Discovered
Pierre Curie and Marie Curie   
Marc Delafontaine   
Discovery
In 1898   
In 1878   
Abundance
  
  
Abundance In Universe
Not Available   
5 * 10-8 %   
27
Abundance In Meteorites
Not Available   
0.00 %   
99+
Abundance In Earth's Crust
Not Available   
0.00 %   
38
Abundance In Oceans
0.00 %   
99+
0.00 %   
99+
Uses
Uses & Benefits
  • Polonium metal has different Allotropes, it is used in antistatic devices and for research purpose.
  • A 1 gram of Polonium can reach a temperature of 500°C, hence it is used as a heat source for space equipment.
  
  • 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.
  
Industrial Uses
Aerospace Industry, Ammunition Industry   
NA   
Medical Uses
NA   
NA   
Other Uses
Alloys   
Alloys, Nuclear Research   
Biological Properties
  
  
Toxicity
Highly Toxic   
Low Toxic   
Present in Human Body
No   
No   
In Blood
0.00 Blood/mg dm-3   
37
Not Available   
In Bone
0.00 p.p.m.   
36
Not Available   
Physical Properties
Melting Point
254.00 °C   
99+
1,461.00 °C   
30
Boiling Point
962.00 °C   
99+
2,600.00 °C   
99+
Appearance
  
  
Physical State
Solid   
Solid   
Color
Silver   
Silvery White   
Luster
NA   
Metallic   
Hardness
  
  
Brinell Hardness
Not Available   
746.00 MPa   
13
Vickers Hardness
Not Available   
481.00 MPa   
23
Speed of Sound
Not Available   
2,760.00 m/s   
30
Optical Properties
  
  
Allotropes
Yes   
No   
α Allotropes
α-polonium   
Not Available   
β Allotropes
β-polonium   
Not Available   
γ Allotropes
Not Available   
Not Available   
Chemical Properties
Chemical Formula
Po   
Ho   
Isotopes
  
  
Known Isotopes
29   
10
34   
5
Electronegativity
  
  
Pauling Electronegativity
2.00   
7
1.23   
37
Allred Rochow Electronegativity
1.76   
2
1.10   
30
Mulliken-Jaffe Electronegativity
2.48   
1
Not Available   
Allen Electronegativity
2.19   
2
Not Available   
Electropositivity
  
  
Pauling Electropositivity
2.00   
99+
2.77   
17
Ionization Energies
  
  
1st Energy Level
812.10 kJ/mol   
14
581.00 kJ/mol   
99+
2nd Energy Level
Not Available   
1,140.00 kJ/mol   
99+
3rd Energy Level
Not Available   
2,204.00 kJ/mol   
99+
4th Energy Level
Not Available   
4,100.00 kJ/mol   
34
Electrochemical Equivalent
3.90 g/amp-hr   
8
2.02 g/amp-hr   
29
Electron Work Function
Not Available   
Not Available   
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility   
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility   
Atomic Properties
Atomic Number
84   
32
67   
99+
Electron Configuration
[Xe] 4f14 5d10 6s2 6p4   
[Xe] 4f11 6s2   
Crystal Structure
Monoclinic (MON)   
Hexagonal Close Packed (HCP)   
Crystal Lattice
MON-Crystal-Structure-of-Polonium.jpg#100   
HCP-Crystal-Structure-of-Holmium.jpg#100   
Atom
  
  
Number of Protons
84   
32
67   
99+
Number of Neutrons
125   
19
98   
34
Number of Electrons
84   
32
67   
99+
Radius of an Atom
  
  
Atomic Radius
168.00 pm   
23
176.00 pm   
18
Covalent Radius
140.00 pm   
99+
192.00 pm   
17
Van der Waals Radius
197.00 pm   
29
216.00 pm   
24
Atomic Weight
209.00 amu   
28
164.93 amu   
99+
Atomic Volume
22.23 cm3/mol   
13
18.70 cm3/mol   
24
Adjacent Atomic Numbers
  
  
Previous Element
Bismuth
  
Dysprosium
  
Next Element
Francium
  
Erbium
  
Valence Electron Potential
Not Available   
47.90 (-eV)   
31
Lattice Constant
335.90 pm   
99+
357.73 pm   
38
Lattice Angles
π/2, π/2, π/2   
π/2, π/2, 2 π/3   
Lattice C/A Ratio
Not Available   
1.57   
17
Mechanical Properties
Density
  
  
Density At Room Temperature
9.20 g/cm3   
99+
8.79 g/cm3   
99+
Density When Liquid (at m.p.)
9.40 g/cm3   
19
8.34 g/cm3   
26
Tensile Strength
Not Available   
Not Available   
Viscosity
Not Available   
Not Available   
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available   
0.00 (Pa)   
16
Elasticity properties
  
  
Shear Modulus
Not Available   
26.30 GPa   
28
Bulk Modulus
Not Available   
40.20 GPa   
32
Young's Modulus
Not Available   
64.80 GPa   
31
Poisson Ratio
Not Available   
0.23   
29
Other Mechanical Properties
NA   
Ductile, Malleable, Sectile   
Magnetic Properties
Magnetic Characteristics
  
  
Specific Gravity
9.32   
31
8.80   
35
Magnetic Ordering
Nonmagnetic   
Paramagnetic   
Electrical Properties
  
  
Electrical Property
Conductor   
Conductor   
Resistivity
0.40 nΩ·m   
99+
814.00 nΩ·m   
4
Electrical Conductivity
0.02 106/cm Ω   
99+
0.01 106/cm Ω   
99+
Electron Affinity
183.30 kJ/mol   
3
50.00 kJ/mol   
21
Thermal Properties
Specific Heat
0.12 J/(kg K)   
40
0.16 J/(kg K)   
35
Molar Heat Capacity
26.40 J/mol·K   
28
27.15 J/mol·K   
19
Thermal Conductivity
20.00 W/m·K   
99+
16.20 W/m·K   
99+
Critical Temperature
Not Available   
Not Available   
Thermal Expansion
23.50 µm/(m·K)   
16
11.20 µm/(m·K)   
35
Enthalpy
  
  
Enthalpy of Vaporization
60.30 kJ/mol   
99+
241.00 kJ/mol   
38
Enthalpy of Fusion
13.00 kJ/mol   
26
11.76 kJ/mol   
29
Enthalpy of Atomization
134.00 kJ/mol   
99+
301.00 kJ/mol   
36
Standard Molar Entropy
Not Available   
75.30 J/mol.K   
8
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