| Ordnungszahl: |
57 |
| Name: |
Lanthanum |
| Namensursprung: |
Greek: lanthanein (to be hidden). |
| Entdeckung: |
1839 by Carl Mosander in Sweden |
| Beschreibung: |
Soft, silvery-white, malleable, ductile metal. |
| Vorkommen: |
Found with rare earths in monazite and bastnasite. Monazite sand typicall contains 25% lanthanum. |
| Verwendung: |
It is used in the electodes of high-intensity, carbon-arc lights. Also used in the production of high-grade europium metal. Because it gives glass refractive properties, it is used in expensive camera lenses. |
| Gruppe: |
Transition Metal |
| Atomgewicht: |
138.9055 |
| Schmelzpunkt: |
918°C |
| Siedepunkt: |
3464°C |
| Dichte bei 293 K: |
6.7 g/cm³ |
| Aggregatszustand bei Raumtemperatur: |
Solid |
| Schalen: |
2,8,18,18,9,2 |
| Orbitale: |
[Xe] 5d1 6s2 |
| Valenzen: |
3 |
| 1. Ionisierungs- potential: |
5.5770 V |
| 2. Ionisierungs- potential: |
11.059 V |
| 3. Ionisierungs- potential: |
19.174 V |
| Atomradius: |
2.74 Å |
| Spezifische Wärme: |
0.19 J/gK |
| Verdampfungswärme: |
414.0 kJ/mol |
| Schmelzwärme: |
6.20 kJ/mol |
| Thermischer Ausdehnungskoeffizient: |
5.2 10-6 K-1 |
| Röntgenemission Energie / Wellenlänge: |
| |
KA |
KB |
LA |
LB |
MA |
MB |
|
|
|
| eV |
0 |
0 |
4651.14 |
5042.29 |
833.235 |
854.482 |
|
|
|
| Å |
0 |
0 |
2.6657 |
2.45891 |
14.88 |
14.51 |
|
|
|
|
| Röntgenabsorption Energie / Wellenlänge: |
| |
K |
L-I |
L-II |
L-III |
M-I |
M-II |
M-III |
M-IV |
M-V |
| eV |
38922 |
6262 |
5891 |
5483 |
1362 |
1205 |
1124 |
0 |
832 |
| Å |
0.31854 |
1.97996 |
2.10466 |
2.26127 |
9.10319 |
10.2892 |
11.0307 |
0 |
14.9021 |
|
| Röntgen Fluoreszenz Ausbeute: |
| |
KA |
KB |
LA |
LB |
MA |
MB |
|
|
|
| |
90.6% |
0% |
13.5% |
0% |
0% |
0% |
|
|
|
|
| Nuklide: |
| |
Anteil |
Gewicht |
Spin |
Halbwertszeit |
Zerfallsmodus |
| La137 |
0% |
137 |
7/2 |
6E04y |
EC |
| La138 |
0.089% |
137.907 |
5 |
1.05E11y |
EC,β- |
| La139 |
99.911% |
138.906 |
7/2 |
|
Stable |
| La140 |
0% |
140 |
3 |
1.678d |
β- |
| La141 |
0% |
141 |
7/2 |
3.90h |
β- |
| La142 |
0% |
142 |
2 |
1.54m |
β- |
|
