Barium

56
Ba
Group
2
Period
6
Block
s
Protons
Electrons
Neutrons
56
56
81
General Properties
Atomic Number
56
Atomic Weight
137.327
Mass Number
137
Category
Alkaline earth metals
Color
Silver
Radioactive
No
From the Greek word barys, heavy
Crystal Structure
Body Centered Cubic
History
Barium was identified as a new element in 1774 by Carl Wilhelm Scheele.

Barium was first isolated by electrolysis of molten barium salts in 1808, by Sir Humphry Davy in England.

Robert Bunsen and Augustus Matthiessen obtained pure barium by electrolysis of a molten mixture of barium chloride and ammonium chloride.
Electrons per shell
2, 8, 18, 18, 8, 2
Electron Configuration
[Xe] 6s2
Ba
At low doses, barium acts as a muscle stimulant
Physical Properties
Phase
Solid
Density
3.594 g/cm3
Melting Point
1000.15 K | 727 °C | 1340.6 °F
Boiling Point
2170.15 K | 1897 °C | 3446.6 °F
Heat of Fusion
8 kJ/mol
Heat of Vaporization
140 kJ/mol
Specific Heat Capacity
0.204 J/g·K
Abundance in Earth's crust
0.034%
Abundance in Universe
1×10-6%
Barium
Image Credits: Images-of-elements
Barium with a grey oxide layer under argon
CAS Number
7440-39-3
PubChem CID Number
5355457
Atomic Properties
Atomic Radius
222 pm
Covalent Radius
215 pm
Electronegativity
0.89 (Pauling scale)
Ionization Potential
5.2117 eV
Atomic Volume
39.24 cm3/mol
Thermal Conductivity
0.184 W/cm·K
Oxidation States
2
Applications
Barium is used as a flashed getter in vacuum tubes to remove the last traces of gases.

It is often used in barium-nickel alloys for spark plug wire.

Barium sulfate is important to the petroleum industry as a drilling fluid in oil and gas wells.

Barium is also used in medicine to detect abnormalities in the digestive system.
Water-soluble barium compounds are poisonous
Isotopes
Stable Isotopes
130Ba, 132Ba, 134Ba, 135Ba, 136Ba, 137Ba, 138Ba
Unstable Isotopes
114Ba, 115Ba, 116Ba, 117Ba, 118Ba, 119Ba, 120Ba, 121Ba, 122Ba, 123Ba, 124Ba, 125Ba, 126Ba, 127Ba, 128Ba, 129Ba, 131Ba, 133Ba, 139Ba, 140Ba, 141Ba, 142Ba, 143Ba, 144Ba, 145Ba, 146Ba, 147Ba, 148Ba, 149Ba, 150Ba, 151Ba, 152Ba, 153Ba