Ac
227.000Actinium
Aktinyum
Actinium is a radioactive actinide with atomic number 89. It begins the actinide series and is known for actinium-225 targeted alpha therapy research, actinium-227, Ac-Be neutron source history and glowing radioactivity.
89
227 g/mol
[Rn] 6d¹ 7s²
2 | 8 | 18 | 32 | 18 | 9 | 2
1.1
10.07 g/cm³
1049.8 °C
3197.8 °C
André-Louis Debierne
Actinium was discovered in 1899 by André-Louis Debierne in uranium ore residues, with independent work by Friedrich Oskar Giesel soon after. Its name comes from Greek aktis, meaning ray or beam.
Actinium-225
Half-life: About 9.92 days. Alpha-emitting isotope studied and used in targeted alpha therapy radiopharmaceuticals.Actinium-227
Half-life: About 21.8 years. Naturally occurring isotope in the uranium-235 decay series.AcCl₃
Actinium(III) ChlorideResearch compound for actinium chemistry.[²²⁵Ac]Ac-PSMA-617
Actinium-225 PSMATargeted alpha therapy radiopharmaceutical research for prostate cancer.Ac₂O₃
Actinium(III) OxideResearch material in actinium chemistry.- Actinium-225 targeted alpha therapy research and clinical radiopharmaceutical development
- Actinium-225 to bismuth-213 generator systems
- Historical actinium-beryllium neutron source research
- Fundamental actinide chemistry and radiochemistry studies
Actinium has no biological role and all isotopes are radioactive. Actinium-225 radioconjugates are being developed for targeted alpha therapy in nuclear medicine.
- Actinium gives its name to the actinide series, although early actinide chemistry often resembles lanthanum chemistry.
- Actinium-225 decay can release multiple alpha particles through its decay chain.
- Actinium glows faintly in the dark because radiation excites surrounding air and materials.
- Ac-225 supply is a major practical challenge for expanding targeted alpha therapy research.
- Actinium has atomic number 89 and symbol Ac.
- Its electron configuration is [Rn] 6d¹ 7s².
- Actinium commonly forms +3 compounds.
- Remember Ac-225 for targeted alpha therapy and Ac-227 for the natural decay series.
What is the atomic number of actinium?
The atomic number of actinium is 89.
What is the electron configuration of actinium?
Actinium has the electron configuration [Rn] 6d¹ 7s².
What is actinium used for?
Actinium is used mainly in radiopharmaceutical research, especially Ac-225 targeted alpha therapy, and in actinide chemistry studies.
What is actinium-225 used for?
Actinium-225 is an alpha-emitting isotope used in targeted alpha therapy radiopharmaceuticals and clinical research.
What is actinium-227?
Actinium-227 is a naturally occurring radioactive isotope with a half-life of about 21.8 years.
Is actinium an actinide?
Yes. Actinium is the first element of the actinide series.