Symbol
Ba
  
Hf
  
Period Number
6
  
6
  
Block
s block
  
d block
  
Element Family
Alkaline Earth
  
Transition Metal
  
Space Group Name
Im_ 3m
  
P63/mmc
  
Interesting Facts
- Barium oxidizes very easily in the air.
- All toxic compounds of Barium can easily dissolve in water.
- Barium carbonate is used to produce a Rat poison and its other compound Barium nitrate is used in fireworks to produce green color.
  
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
Sources
Earth's crust, Found in Minerals, Mining, Ores of Minerals
  
By-product Zirconium Refining
  
History
  
  
Who Discovered
Carl Wilhelm Scheele
  
Dirk Coster and George de Hevesy
  
Discovery
In 1772
  
In 1922
  
Abundance
  
  
Abundance In Sun
~0.000001 %
  
18
~0.0000001 %
  
26
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
Uses & Benefits
- It is sued in chemical paint manufacturing and glass manufacturing.
-
Compounds of this metal are toxic; but still the barium sulfate is insoluble and given to patients suffering from digestive disorder.
  
- It has an ability to absorb neutrons and hence it is used to make control rods in nuclear submarines. And this metal is also used in Plasma welding torches.
-
It alloys with iron, titanium and niobium are very useful.
  
Industrial Uses
Ammunition Industry, Automobile Industry, Electrical Industry, Electronic Industry
  
Ammunition Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Biological Properties
  
  
Toxicity
Low Toxic
  
Toxic
  
Present in Human Body
Yes
  
No
  
In Blood
0.07 Blood/mg dm-3
  
15
Not Available
  
In Bone
70.00 p.p.m.
  
9
Not Available
  
Melting Point
2,150.00 °C
  
10
Boiling Point
1,140.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery Gray
  
Gray
  
Luster
NA
  
Metallic
  
Hardness
  
  
Brinell Hardness
Not Available
  
1,450.00 MPa
  
6
Vickers Hardness
Not Available
  
1,520.00 MPa
  
5
Speed of Sound
1,620.00 m/s
  
99+
3,010.00 m/s
  
27
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
Ba
  
Hf
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
502.90 kJ/mol
  
99+
658.50 kJ/mol
  
40
2nd Energy Level
965.20 kJ/mol
  
99+
1,440.00 kJ/mol
  
99+
3rd Energy Level
3,600.00 kJ/mol
  
14
2,250.00 kJ/mol
  
99+
4th Energy Level
Not Available
  
3,216.00 kJ/mol
  
99+
Electrochemical Equivalent
2.56 g/amp-hr
  
20
1.66 g/amp-hr
  
99+
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 6s2
  
[Xe] 4f14 5d2 6s2
  
Crystal Structure
Body Centered Cubic (BCC)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
137.33 amu
  
99+
Atomic Volume
39.24 cm3/mol
  
5
13.60 cm3/mol
  
38
Adjacent Atomic Numbers
  
  
Valence Electron Potential
21.30 (-eV)
  
99+
81.00 (-eV)
  
16
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
3.51 g/cm3
  
99+
13.31 g/cm3
  
26
Density When Liquid (at m.p.)
3.34 g/cm3
  
99+
12.00 g/cm3
  
12
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
NA
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Superconductor
  
Conductor
  
Resistivity
332.00 nΩ·m
  
13
331.00 nΩ·m
  
14
Electrical Conductivity
0.03 106/cm Ω
  
40
0.03 106/cm Ω
  
39
Electron Affinity
13.95 kJ/mol
  
36
0.00 kJ/mol
  
40
Specific Heat
0.20 J/(kg K)
  
30
0.14 J/(kg K)
  
37
Molar Heat Capacity
28.07 J/mol·K
  
12
25.73 J/mol·K
  
36
Thermal Conductivity
18.40 W/m·K
  
99+
23.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
20.60 µm/(m·K)
  
22
5.90 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
140.00 kJ/mol
  
99+
661.10 kJ/mol
  
5
Enthalpy of Fusion
7.66 kJ/mol
  
99+
25.10 kJ/mol
  
8
Enthalpy of Atomization
175.70 kJ/mol
  
99+
703.00 kJ/mol
  
5
Standard Molar Entropy
62.50 J/mol.K
  
20
43.60 J/mol.K
  
34