Ordnungszahl: |
56 |
Name: |
Barium |
Namensursprung: |
Greek: barys (heavy or dense). |
Entdeckung: |
1808 by Sir Humphrey Davy in England |
Beschreibung: |
Soft, slightly malleable, silvery-white metal. |
Vorkommen: |
Found in barytine (BaSO4) and witherite (BaCO3), never found in pure form due to its reactivity. Must be stored under kerosene to remain pure. |
Verwendung: |
Barite, or barium sulfate, 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 burns
brilliant green and is used in fireworks. |
Gruppe: |
Alkali Earth Metal |
Atomgewicht: |
137.327 |
Schmelzpunkt: |
725°C |
Siedepunkt: |
1897°C |
Dichte bei 293 K: |
3.51 g/cm³ |
Aggregatszustand bei Raumtemperatur: |
Solid |
Schalen: |
2,8,18,18,8,2 |
Orbitale: |
[Xe] 6s2 |
Valenzen: |
2 |
1. Ionisierungs- potential: |
5.2117 V |
2. Ionisierungs- potential: |
10.004 V |
3. Ionisierungs- potential: |
-- |
Atomradius: |
2.78 Å |
Spezifische Wärme: |
0.204 J/gK |
Verdampfungswärme: |
142.0 kJ/mol |
Schmelzwärme: |
7.750 kJ/mol |
Thermischer Ausdehnungskoeffizient: |
20.6 10-6 K-1 |
Röntgenemission Energie / Wellenlänge: |
|
KA |
KB |
LA |
LB |
MA |
MB |
|
|
|
eV |
0 |
0 |
4466.41 |
4827.70 |
0 |
0 |
|
|
|
Å |
0 |
0 |
2.77595 |
2.56821 |
0 |
0 |
|
|
|
|
Röntgenabsorption Energie / Wellenlänge: |
|
K |
L-I |
L-II |
L-III |
M-I |
M-II |
M-III |
M-IV |
M-V |
eV |
37438 |
5989 |
5624 |
5247 |
1293 |
1137 |
1063 |
796.7 |
780.1 |
Å |
0.33117 |
2.07022 |
2.20458 |
2.36298 |
9.58897 |
10.9046 |
11.6637 |
15.5624 |
15.8935 |
|
Röntgen Fluoreszenz Ausbeute: |
|
KA |
KB |
LA |
LB |
MA |
MB |
|
|
|
|
90% |
0% |
12.6% |
0% |
0% |
0% |
|
|
|
|
Nuklide: |
|
Anteil |
Gewicht |
Spin |
Halbwertszeit |
Zerfallsmodus |
Ba130 |
0.101% |
129.906 |
0 |
|
Stable |
Ba131 |
0% |
131 |
1/2 |
11.7d |
EC,β+ |
Ba132 |
0.097% |
131.905 |
0 |
|
Stable |
Ba133 |
0% |
133 |
1/2 |
10.53y |
EC |
Ba133m |
0% |
133 |
11/2 |
1.621d |
IT,EC |
Ba134 |
2.42% |
133.905 |
0 |
|
Stable |
Ba135 |
6.59% |
134.906 |
3/2 |
|
Stable |
Ba135m |
0% |
135 |
11/2 |
1.20d |
IT |
Ba136 |
7.81% |
135.905 |
0 |
|
Stable |
Ba137 |
11.32% |
137.906 |
3/2 |
|
Stable |
Ba137m |
0% |
137 |
11/2 |
2.552m |
IT |
Ba138 |
71.66% |
137.905 |
0 |
|
Stable |
Ba139 |
0% |
139 |
7/2 |
1.396h |
β- |
Ba140 |
0% |
140 |
0 |
12.75d |
β- |
Ba141 |
0% |
141 |
3/2 |
18.3m |
β- |
Ba142 |
0% |
142 |
0 |
10.7m |
β- | |