Furthermore, the now-known chemistry of actinium precludes its presence as anything other than a minor constituent of Debierne's 1899 and 1900 results; in fact, the chemical properties he reported make it likely that he had, instead, accidentally identified protactinium, which would not be discovered for another fourteen years, only to have it disappear due to its hydrolysis and adsorption onto his laboratory equipment.
Nadalje, sada poznata kemija aktinija isključuje njegovu prisutnost kao bilo što drugo osim manjeg sastava Debierneove 1899. i 1900. godine; zapravo, kemijska svojstva o kojima je izvijestio čine da je vjerojatno imao slučajno identificirani protaktinium, koji ne bi bio otkriven još četrnaest godina, samo da bi nestao zbog njegove hidrolize i adsorpcije na laboratorijsku opremu.