|Name, Symbol, Number||Barium, Ba, 56 |
|Series||alkaline earth metals|
|Group, Period, Block||2(IIA), 6, s|
|Density, Hardness||3510 kg/m3, 1.25|
|Atomic weight||137.327 amu|
|Atomic radius (Calc.)||215 pm (253 pm)|
|Covalent radius||198 pm|
|van der Waals radius||no information|
|Electron configuration ||[Xe]6s6s2|
|e- 's per energy level||2, 8, 18, 18, 8, 2|
|Oxidation states (Oxide)||2 (strong base)|
|Crystal structure||Cubic body centered|
|State of matter||solid (paramagnetic)|
|Melting point||1000 K (1341 °F)|
|Boiling point||2143 K (3398 °F)|
|Molar volume||38.16 ×1010-3 m3/mol|
|Heat of vaporization||142 kJ/mol|
|Heat of fusion||7.75 kJ/mol|
|Vapor pressure||98 Pa at 371 K|
|Speed of sound||1620 m/s|
|Electronegativity||0.89(Pauling scale) |
|Specific heat capacity||204 J/(kg*K)|
|Electrical conductivity||3 106/m ohm|
|Thermal conductivity|| 18.4 W/(m*K)|
|1st ionization potential||502.9 kJ/mol|
|2nd ionization potential||965.2 kJ/mol|
|3rd ionization potential||3600 kJ/mol|
|Most Stable Isotopes|
|iso||NA||half-life ||DM||DE MeV||DP|
|130Ba||0.106%||Ba is stable with 74 neutrons|
|132Ba||0.101%||Ba is stable with 76 neutrons|
|134Ba||2.417%||Ba is stable with 78 neutrons|
|135Ba||6.592%||Ba is stable with 79 neutrons|
|136Ba||7.854%||Ba is stable with 80 neutrons|
|137Ba||11.23%||Ba is stable with 81 neutrons|
|138Ba||71.7%||Ba is stable with 82 neutrons|
|SI units & STP are used except where noted.
is a chemical element
in the periodic table
that has the symbol Ba and atomic number
56. A soft silvery metallic element, barium is an alkaline earth metal
and melts at a very high temperature
. Its oxide is called baryta
and it is primarily found in the mineral barite
but is never found in its pure form due to its reactivity with air
. Compounds of this metal are used in small quantities in paints and in glassmaking.
Barium is a metallic element that is chemically similar to calcium, yet is soft and in its pure form is silvery white resembling lead.
This metal oxidizes very easily and when exposed to air and is highly reactive with water or alcohol.
Barium is decomposed by water or alcohol. Some of the compounds of this element are remarkable for their high specific gravity, as its sulphate, called heavy spar.
Barium is primarily used in sparkplugs, vacuum tubes, fireworks, and in fluorescent lamps.
- A "getter" in vacuum tubes.
- Barium sulfate is permanent white and is used in paint, in X-ray diagnostic work, and in glassmaking.
- Barite is used extensively as a weighing agent in oil well drilling fluids and in rubber production.
- Barium carbonate is a useful rat poison, while barium nitrate and chlorate give colors in fireworks.
- Impure barium sulfide phosphoresces after exposure to the light.
- Barium salts are sometimes used in medical procedures, such as X-raying the digestive system.
- Lithopone, a pigment that contains barium sulfate and zinc sulfide, has good covering power, and does not darken in when exposed to sulfides.
"barys" meaning "heavy") was first identified in 1774
by Carl Scheele
and extracted in 1808
by Sir Humphry Davy
The oxide was at first called barote, by Guyton de Morveau, which was changed by Antoine Lavoisier
to baryta, which soon was modified to "barium" to describe the metal.
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 mineral barite
which is crystalized barium sulphate.
Barium is commercially produced through the electrolysis
of molten barium chloride (BaCl2
* + 2e-
---> Ba (anode
* --> ½Cl2
) + e-
The most important compounds are barium peroxide, chloride, sulfate, carbonate, nitrate, and chlorate.
When burned, barium salts glows green. (See "Uses" section above)
Naturally occurring barium is a mix of seven stable isotopes
. There are twenty-two isotopes known, but most of these are highly radioactive
and have half-lifes in the several millisecond to several minute range. The only notable exception is barium-133 which has a half-life of 10.51 years.
All water or acid soluble barium compounds are extremely poisonous.
occurs very easily and to remain pure, barium should be kept under a petroleum-based fluid (such as kerosene
) or other suitable oxygen
-free liquids that exclude air.
Barium is also the latin name for the city Bari in Italy.