|
General |
Name, Symbol, Number | Barium, Ba, 56 |
Series | alkaline earth metals |
Group, Period, Block | 2(IIA), 6, s |
Density, Hardness | 3510 kg/m3, 1.25 |
Appearance | silvery white |
Atomic Properties |
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]6s2 |
e- 's per energy level | 2, 8, 18, 18, 8, 2 |
Oxidation states (Oxide) | 2 (strong base) |
Crystal structure | Cubic body centered |
Physical Properties |
State of matter | solid (paramagnetic) |
Melting point | 1000 K (1341 °F) |
Boiling point | 2143 K (3398 °F) |
Molar volume | 38.16 ×10-3 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 |
Miscellaneous |
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 |
133Ba | {syn.} | 10.51 y | epsilon | 0.517 | 133Cs |
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. |
Barium 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.
Also:
Barium (
Greek "barys" meaning "heavy") was first identified in
1774 by
Carl Scheele and extracted in
1808 by Sir
Humphry Davy in
England.
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[?] (Ba
Cl2)
Isolation (* follow):
(
cathode) Ba
2+* + 2
e- ---> Ba (
anode) Cl
-* --> ½Cl
2 (
g) + 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.
Oxidation 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.