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- | |