Actinium

89
Ac
Gruppe
n/a
Periode
7
Block
f
Protonen
Elektronen
Neutronen
89
89
138
Generelle Eigenschaften
Ordnungszahl
89
Atommasse
[227]
Massenzahl
227
Kategorie
Actinoide
Farbe
Silber
Radioaktiv
Ja
From the Greek aktis, aktinos, meaning beam or ray
Kristallstruktur
Kubisch flächenzentriert
Geschichte
André-Louis Debierne, a French chemist, discovered actinium in 1899.

He separated it from pitchblende residues left by Marie and Pierre Curie after they had extracted radium.

Friedrich Oskar Giesel independently discovered actinium in 1902 as a substance being similar to lanthanum.
Elektronen pro Schale
2, 8, 18, 32, 18, 9, 2
Elektronenkonfiguration
[Rn] 6d1 7s2
Ac
Actinium glows in the dark with a pale blue light
Physikalische Eigenschaften
Aggregatzustand
Fest
Dichte
10,07 g/cm3
Schmelzpunkt
1323,15 K | 1050 °C | 1922 °F
Siedepunkt
3471,15 K | 3198 °C | 5788,4 °F
Schmelzwärme
14 kJ/mol
Verdampfungswärme
400 kJ/mol
Spezifische Wärmekapazität
0,12 J/g·K
Häufigkeit in der Erdkruste
n/a
Häufigkeit im Universum
n/a
Illustration
Danksagungen für Bilder: Images-of-elements
Illustration of actinium
CAS-Nummer
7440-34-8
PubChem CID Number
n/a
Atomeigenschaften
Atomradius
-
Kovalenter Radius
215 pm
Elektronegativität
1,1 (Pauling-Skala)
Ionisierungsenergie
5,17 eV
Molares Volumen
22,54 cm3/mol
Wärmeleitfähigkeit
0,12 W/cm·K
Oxidationszustände
3
Anwendung
Actinium is used as an active element of radioisotope thermoelectric generators, for example in spacecraft.

The medium half-life of 227Ac makes it very convenient radioactive isotope in modeling the slow vertical mixing of oceanic waters.

225Ac is applied in medicine to produce 213Bi in a reusable generator or can be used alone as an agent for radiation therapy.
Actinium is highly radioactive
Isotope
Stabile Isotope
-
Instabile Isotope
206Ac, 207Ac, 208Ac, 209Ac, 210Ac, 211Ac, 212Ac, 213Ac, 214Ac, 215Ac, 216Ac, 217Ac, 218Ac, 219Ac, 220Ac, 221Ac, 222Ac, 223Ac, 224Ac, 225Ac, 226Ac, 227Ac, 228Ac, 229Ac, 230Ac, 231Ac, 232Ac, 233Ac, 234Ac, 235Ac, 236Ac