Barium
Barium (von griech. βαρύς: schwer, wegen der großen Dichte des Bariumminerals Baryt) ist ein chemisches Element mit dem Symbol Ba und der Ordnungszahl 56.
| 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- | |
