Symbol
Po
  
Sr
  
Period Number
6
  
5
  
Block
p block
  
s block
  
Element Family
Post-Transition
  
Alkaline Earth
  
Space Group Name
Pm-3m
  
Fm_ 3m
  
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.
  
- Strontium element is softer than Calcium.
- Silvery Strontium turns yellow, if exposed to air.
  
Sources
Mining, Ores of metals
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Pierre Curie and Marie Curie
  
William Cruickshank
  
Discovery
In 1898
  
In 1787
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
~0.000005 %
  
15
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Abundance In Humans
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.
  
- Strontium metal is used to producing ferrite magnets as well as refining zinc.
-
By-product of nuclear reactors called Strontium-90 is a radioactive isotope; it is absorbed by tissues and destroys bone marrow and cancer growth.
  
Industrial Uses
Aerospace Industry, Ammunition Industry
  
Ammunition Industry, Chemical Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Non Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
0.00 Blood/mg dm-3
  
37
0.03 Blood/mg dm-3
  
19
In Bone
0.00 p.p.m.
  
36
140.00 p.p.m.
  
7
Boiling Point
1,384.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silvery White
  
Luster
NA
  
Metallic
  
Hardness
  
  
Mohs Hardness
Not Available
  
Speed of Sound
Not Available
  
Not Available
  
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
  
Sr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
812.10 kJ/mol
  
14
549.50 kJ/mol
  
99+
2nd Energy Level
Not Available
  
1,064.20 kJ/mol
  
99+
3rd Energy Level
Not Available
  
4,138.00 kJ/mol
  
10
4th Energy Level
Not Available
  
5,500.00 kJ/mol
  
13
5th Energy Level
Not Available
  
6,910.00 kJ/mol
  
18
6th Energy Level
Not Available
  
8,760.00 kJ/mol
  
18
7th Energy level
Not Available
  
10,230.00 kJ/mol
  
19
8th Energy Level
Not Available
  
11,800.00 kJ/mol
  
19
9th Energy Level
Not Available
  
15,600.00 kJ/mol
  
17
10th Energy Level
Not Available
  
17,100.00 kJ/mol
  
19
11th Energy Level
Not Available
  
31,270.00 kJ/mol
  
6
Electrochemical Equivalent
3.90 g/amp-hr
  
8
1.64 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Electron Configuration
[Xe] 4f14 5d10 6s2 6p4
  
[Kr] 5s2
  
Crystal Structure
Monoclinic (MON)
  
Face Centered Cubic (FCC)
  
Crystal Lattice
MON-Crystal-Structure-of-Polonium.jpg#100
  
FCC-Crystal-Structure-of-Strontium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
22.23 cm3/mol
  
13
33.70 cm3/mol
  
6
Adjacent Atomic Numbers
  
  
Valence Electron Potential
Not Available
  
25.70 (-eV)
  
99+
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
9.20 g/cm3
  
99+
2.64 g/cm3
  
99+
Density When Liquid (at m.p.)
2.38 g/cm3
  
99+
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
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Nonmagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
NA
  
Resistivity
132.00 nΩ·m
  
24
Electrical Conductivity
0.02 106/cm Ω
  
99+
0.08 106/cm Ω
  
26
Electron Affinity
183.30 kJ/mol
  
3
5.03 kJ/mol
  
38
Specific Heat
0.12 J/(kg K)
  
40
0.30 J/(kg K)
  
18
Molar Heat Capacity
26.40 J/mol·K
  
28
26.40 J/mol·K
  
28
Thermal Conductivity
20.00 W/m·K
  
99+
35.40 W/m·K
  
37
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
23.50 µm/(m·K)
  
16
22.50 µm/(m·K)
  
18
Enthalpy
  
  
Enthalpy of Vaporization
60.30 kJ/mol
  
99+
150.00 kJ/mol
  
99+
Enthalpy of Fusion
13.00 kJ/mol
  
26
9.16 kJ/mol
  
38
Enthalpy of Atomization
134.00 kJ/mol
  
99+
163.20 kJ/mol
  
99+
Standard Molar Entropy
Not Available
  
55.00 J/mol.K
  
26