What is actinium

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Actinium is a chemical element that has the atomic number 89. Its mass number is 227 and it is represented by the symbol Ac. It is the first member of the actinide series. It is an f-block element in period 7. It has 89 electrons and 138 neutrons. Its electronegativity is 1.1 (Pauling scale) and its oxidation state is +3. Its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 6d¹ 7s². The energy required for 1^st ionization is 499 kJ/mol and for 2^nd is 1170 kJ/mol. Actinium has no stable isotope all are radioisotopes. There are 32 radioisotopes of Actinium.

At STP it is in solid-state and has a density of 10 g/cm³. Its melting point is 1323.15 K (1050 °C, 1922 °F) and its boiling point is 3500±300 K ?(3200±300 °C, ?5800±500 °F). Actinium is a soft radioactive metallic element with a silvery-white appearance. It quickly reacts with moisture and oxygen turning into the white colour of Actinium oxide.

It is found in uranium ores (Uraninite) in trace amounts. It can also be found in thorium ores. Actinium isotope Ac-227 is a product of Uranium decay of U-235. It can also be produced in nuclear reactors through the neutron irradiation of Ra-226.

Its scarcity makes its price very high and due to its radioactivity, it has no significant industrial use. But research is showing that it can be effective against leukaemia, lymphoma, breast, ovarian, neuroblastoma and prostate cancers.

Who discovered actinium?

The discovery of Actinium is a little controversial between André-Louis Debierne and Friedrich Oskar Giesel. André-Louis Debierne announced the discovery of a new element in 1899. Which he separated from the pitchblende residues. Debierne described it as similar to titanium. Debierne's results published in 1904 conflict with those reported in 1899 and 1900. But Debierne's chosen name for the new element was retained because it had seniority.