Actinium

From Citizendium, the Citizens' Compendium
Jump to: navigation, search
This article is a stub and thus not approved.
Main Article
Talk
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
Properties [?]
 
This editable Main Article is under development and not meant to be cited; by editing it you can help to improve it towards a future approved, citable version. These unapproved articles are subject to a disclaimer.
Actinium
227



  Ac
89
1s22s22p63s23p63d104s24p6 4d105s25p64f145d106s26p66d17s2
[ ? ] Transition metal:


Actinium is a chemical element, having the chemical symbol Ac. Its atomic number (the number of protons) is 89. It has a standard atomic weight of 227 g•mol −1 and it is a solid in its elemental form.

Actinium is considered a member of the "Transition metal" class of elements. At a pressure of 101.325 kPa, it has a boiling point of 3,198 °C and a melting point of 1,051 °C.

History

Actinium has been discovered in 1899 by André-Louis Debierne, and independently by F. Giesel in 1902. This element was named from the Greek word aktis, aktinos (ακτίς, ακτίνος), meaning beam or ray.[1]

References

  1. William M.Haynes (2010). Handbook of Chemistry and Physics, 91st Edition. CRC Press. ISBN 1-4398-2077-5.