21. Actinium also has two meta states.22. The major difficulty in separation of actinium is the similarity of its properties with those of lanthanum. 23. Update : I think the actinium that the site sells is actually a compound ( nitrate ). 24. All but two tested positive for actinium -227, the radioactive isotope the workers were cleaning up. 25. It is the ninth product of the neptunium decay series as a daughter isotope of actinium -225. 26. Actinium can be made in reasonable amounts, and has a decent half-life of 21 years.27. Sullivan said actinium -227 tends to accumulate in the liver, but he downplayed the potential health risk. 28. Protactinium is more abundant ( 10 " 12 % ) in the Earth's crust than actinium . 29. Thus actinium is either synthesized in nuclear reactions from isotopes of radium or separated using ion-exchange procedures. 30. Chemically, actinium is similar to lanthanum, which is explained by their similar ionic radii and electronic structure.
