Barium



56 lanthanum
Ra
General
Number barium, Ba, 56
alkaline earth metals
Block s
Appearance silvery white
(7)  g·mol−1
Xe] 6s2
shell 2, 8, 18, 18, 8, 2
Physical properties
Phase solid
r.t.) 3.51  g·cm−3
Liquid m.p. 3.338  g·cm−3
F)
F)
kJ·mol−1
kJ·mol−1
Heat capacity (25 °C) 28.07  J·mol−1·K−1
Vapor pressure
P(Pa) 1 10 100 1 k 10 k 100 k
at T(K) 911 1038 1185 1388 1686 2170
Atomic properties
Crystal structure cubic body centered
basic oxide)
Electronegativity 0.89 (Pauling scale)
Ionization energies 1st: 502.9 kJ/mol
2nd: 965.2 kJ/mol
3rd: 3600 kJ/mol
Atomic radius 215  pm
Atomic radius (calc.) 253  pm
Covalent radius 198  pm
Miscellaneous
paramagnetic
Electrical resistivity (20 °C) 332 n Ω·m
Thermal conductivity (300 K) 18.4  W·m−1·K−1
Thermal expansion (25 °C) 20.6  µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 1620 m/s
Young's modulus 13  GPa
Shear modulus 4.9  GPa
Bulk modulus 9.6  GPa
Mohs hardness 1.25
CAS registry number 7440-39-3
Selected isotopes
Main article: Isotopes of barium
iso NA half-life DM DE (MeV) DP
130Ba 0.106% Ba is neutrons
132Ba 0.101% Ba is neutrons
133Ba syn 10.51 y ε 0.517 133Cs
134Ba 2.417% Ba is neutrons
135Ba 6.592% Ba is neutrons
136Ba 7.854% Ba is neutrons
137Ba 11.23% Ba is neutrons
138Ba 71.7% Ba is neutrons
References

Barium (Benitoite is a rare gem containing barium.

Notable characteristics

Barium is a barite BaSO4, also called 'heavy spar' due to the high density (4.5 g/cm³).

Applications

Barium has some medical and many industrial uses:

  • Barium compounds, and especially barite (BaSO4), are extremely important to the petroleum industry. Barite is used in drilling mud, a weighting agent in drilling new oil wells.
  • barium enemas").
  • bricks. Unlike the sulfate, the carbonate dissolves in stomach acid, allowing it to be poisonous.
  • An alloy with nickel is used in spark plug wire.
  • Barium oxide is used in a coating for the electrons.
  • The metal is a "getter" in vacuum tubes, to remove the last traces of oxygen.
  • refractive index and luster of the glass.
  • rubber production.
  • Barium nitrate and chlorate give green colors in fireworks.
  • Impure light.
  • Lithopone, a barium sulfate and zinc sulfide, is a permanent white that has good covering power, and does not darken in when exposed to sulfides.
  • Barium peroxide can be used as a catalyst to start an aluminothermic reaction when welding rail tracks together. It can also be used in green tracer ammunition.
  • Barium titanate was proposed in 2007[1] to be used in next generation battery technology for electric cars.
  • Barium Fluoride is used in infrared applications.
  • Barium is a key element in YBCO superconductors.

History

Barium (Greek barys, meaning "heavy") was first identified in 1774 by Antoine Lavoisier to baryta, from which "barium" was derived to describe the metal.

Occurrence

Because barium quickly becomes oxidized in air, it is difficult to obtain this metal in its pure form. It is primarily found in and extracted from the barium chloride (BaCl2) Isolation (* follow):

(g) + e-

Compounds

The most important compounds are barium peroxide, barium chloride, carbonate, nitrate, and chlorate.

Isotopes

Main article: isotopes of barium

Naturally occurring barium is a mix of seven stable half-lives in the several millisecond to several minute range. The only notable exceptions are 133Ba which has a half-life of 10.51 years, and 137mBa (2.55 minutes).

Precautions

All water or acid potassium ion channels which are critical to the proper function of the nervous system.

baritosis.

oxygen-free liquids that exclude air.

Barium acetate could lead to death in high doses. Marie Robards poisoned her father with the substance in Texas in 1993. She was tried and convicted in 1996.

References

  1. ^ http://www.epa.gov/region5/superfund/ecology/html/toxprofiles.htm#ba
 
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