Actinium

	Main Article	Discussion	Related Articles  [?]	Bibliography  [?]	External Links  [?]	Citable Version  [?]	Properties [?]
	This editable Main Article is under development and subject to a disclaimer. [edit intro]

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[edit]

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[edit]