Barium

Barium (Ba)

Silvery-white reactive element, belonging to group 2 of the periodic table. Soluble barium compounds are extremely poisonous. Identified in 1774 by Karl Scheele and extracted in 1808 by Humphry Davy.
Atomic Number56
Atomic Weight137.327
Mass Number138
Group2
Period6
Blocks
Protons56 p+
Neutrons82 n0
Electrons56 e-
Barium 1.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
215 pm
Atomic Volume
Covalent Radius
196 pm
Metallic Radius
198 pm
Ionic Radius
135 pm
Crystal Radius
149 pm
Van der Waals radius
268 pm
Density
3.62 g/cm³
Boiling Point
1,910 K
Melting Point
1,002 K
Electrons per shell2, 8, 18, 18, 8, 2
Electronegativity
0.89
Electrophilicity
0.707754321076 eV/particle
Proton Affinity
Electron Affinity
0.14462 eV/particle
Ionization Potential
5.211664 eV/particle
Heat of Vaporization
142 kJ/mol
Heat of Fusion
7.66 kJ/mol
Heat of Formation
179.1 kJ/mol
Molar Heat Capacity
28.07 J/(mol K)
Specific Heat Capacity
0.204 J/(g⋅K)
Thermal Conductivity
Gas Basicity
Dipole Polarizability
272 a₀
C6 Dispersion Coefficient
Oxidation States2
Color
Silver
Crystal StructureBody Centered Cubic (BCC)
Lattice Constant
5.02 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Xe] 6s2
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryAlkaline earth metals, Alkaline earth metals
CAS GroupIIA
IUPAC GroupIIA
Glawe Number14
Mendeleev Number9
Pettifor Number14
Geochemical Classalkaline earth metal
Goldschmidt Classlitophile
Radioactivity
RadioactiveNo
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
425 mg/kg
Abundance in Oceans
0.013 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe1×10-6%

Isotopes of Barium

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

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. From the Greek word barys, heavy

DiscoverersSir Humphrey Davy
Discovery LocationEngland
Discovery Year1808
Name OriginGreek: barys (heavy or dense).
Water-soluble barium compounds are poisonous
At low doses, barium acts as a muscle stimulant

Uses

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. Barite, or barium sulfate (BaSO4), when ground is used as a filter for rubber, plastics, and resins. It is insoluable in water and so is used in X-rays of the digestive system. Barium nitrate, Ba(NO3)2, burns brilliant green and is used in fireworks.

Sources

Found in barytine (BaSO4) and witherite (BaCO3), never found in pure form due to its reactivity. Must be stored under kerosene to remain pure.