Symbol
Po
  
Ho
  
Group Number
Not Available
  
Period Number
6
  
6
  
Block
p block
  
f block
  
Element Family
Post-Transition
  
Lanthanide
  
Space Group Name
Pm-3m
  
P63/mmc
  
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
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
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
  
Melting Point
1,461.00 °C
  
30
Boiling Point
2,600.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silvery White
  
Luster
NA
  
Metallic
  
Hardness
  
  
Brinell Hardness
Not Available
  
Vickers Hardness
Not Available
  
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 Formula
Po
  
Ho
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
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
  
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
  
  
Radius of an Atom
  
  
Atomic Weight
164.93 amu
  
99+
Atomic Volume
22.23 cm3/mol
  
13
18.70 cm3/mol
  
24
Adjacent Atomic Numbers
  
  
Valence Electron Potential
Not Available
  
47.90 (-eV)
  
31
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
9.20 g/cm3
  
99+
8.79 g/cm3
  
99+
Density When Liquid (at m.p.)
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
Ductile, Malleable, Sectile
  
Magnetic Characteristics
  
  
Magnetic Ordering
Nonmagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
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
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