Symbol
Sr
  
Tl
  
Period Number
5
  
6
  
Block
s block
  
p block
  
Element Family
Alkaline Earth
  
Post-Transition
  
Space Group Name
Fm_ 3m
  
P63/mmc
  
Interesting Facts
- Strontium element is softer than Calcium.
- Silvery Strontium turns yellow, if exposed to air.
  
- Compounds of Thallium metal are highly Toxic.
- Thallium metal is being suspected as a human carcinogen.
  
Sources
Found in Minerals, Mining, Ores of Minerals
  
Found As a By-product, Ores of metals, Ores of Minerals
  
History
  
  
Who Discovered
William Cruickshank
  
William Crookes
  
Discovery
In 1787
  
In 1861
  
Abundance
  
  
Abundance In Sun
~0.000005 %
  
15
~0.0000001 %
  
26
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
Uses & Benefits
- 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.
  
- Thallium is a toxic metal and hence it has limited uses. Thallium metal is mostly used for producing photoelectric cells.
- In thermometer’s mercury alloy has 8% of thallium, as it has a melting point lower than 20°C.
  
Industrial Uses
Ammunition Industry, Chemical Industry
  
Chemical Industry
  
Medical Uses
NA
  
Medical Research
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Non Toxic
  
Highly Toxic
  
Present in Human Body
Yes
  
Yes
  
In Blood
0.03 Blood/mg dm-3
  
19
0.00 Blood/mg dm-3
  
34
In Bone
140.00 p.p.m.
  
7
0.00 p.p.m.
  
33
Boiling Point
1,384.00 °C
  
99+
1,457.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Silvery White
  
Luster
Metallic
  
NA
  
Hardness
  
  
Brinell Hardness
Not Available
  
Speed of Sound
Not Available
  
818.00 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 Formula
Sr
  
Tl
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
549.50 kJ/mol
  
99+
589.40 kJ/mol
  
99+
2nd Energy Level
1,064.20 kJ/mol
  
99+
1,971.00 kJ/mol
  
14
3rd Energy Level
4,138.00 kJ/mol
  
10
2,878.00 kJ/mol
  
32
4th Energy Level
5,500.00 kJ/mol
  
13
Not Available
  
5th Energy Level
6,910.00 kJ/mol
  
18
Not Available
  
6th Energy Level
8,760.00 kJ/mol
  
18
Not Available
  
7th Energy level
10,230.00 kJ/mol
  
19
Not Available
  
8th Energy Level
11,800.00 kJ/mol
  
19
Not Available
  
9th Energy Level
15,600.00 kJ/mol
  
17
Not Available
  
10th Energy Level
17,100.00 kJ/mol
  
19
Not Available
  
11th Energy Level
31,270.00 kJ/mol
  
6
Not Available
  
Electrochemical Equivalent
1.64 g/amp-hr
  
99+
7.63 g/amp-hr
  
2
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Kr] 5s2
  
[Xe] 4f14 5d10 6s2 6p1
  
Crystal Structure
Face Centered Cubic (FCC)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
FCC-Crystal-Structure-of-Strontium.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
33.70 cm3/mol
  
6
17.20 cm3/mol
  
31
Adjacent Atomic Numbers
  
  
Valence Electron Potential
25.70 (-eV)
  
99+
9.60 (-eV)
  
99+
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
2.64 g/cm3
  
99+
11.85 g/cm3
  
31
Density When Liquid (at m.p.)
2.38 g/cm3
  
99+
11.22 g/cm3
  
13
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Bulk Modulus
Not Available
  
Other Mechanical Properties
NA
  
Ductile, Sectile
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Diamagnetic
  
Electrical Properties
  
  
Electrical Property
NA
  
Conductor
  
Resistivity
132.00 nΩ·m
  
24
Electrical Conductivity
0.08 106/cm Ω
  
26
0.06 106/cm Ω
  
32
Electron Affinity
5.03 kJ/mol
  
38
19.20 kJ/mol
  
32
Specific Heat
0.30 J/(kg K)
  
18
0.13 J/(kg K)
  
39
Molar Heat Capacity
26.40 J/mol·K
  
28
26.32 J/mol·K
  
29
Thermal Conductivity
35.40 W/m·K
  
37
46.10 W/m·K
  
33
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
22.50 µm/(m·K)
  
18
29.90 µm/(m·K)
  
12
Enthalpy
  
  
Enthalpy of Vaporization
150.00 kJ/mol
  
99+
162.10 kJ/mol
  
99+
Enthalpy of Fusion
9.16 kJ/mol
  
38
4.27 kJ/mol
  
99+
Enthalpy of Atomization
163.20 kJ/mol
  
99+
179.90 kJ/mol
  
99+
Standard Molar Entropy
55.00 J/mol.K
  
26
64.20 J/mol.K
  
19