The new product exhibited chemical properties of an alkali metal (such as coprecipitating with caesium salts), which led Perey to believe that it was element 87, caused by the alpha decay of actinium-227.
ðə nˈuː pɹˈɑːdʌkt ɛɡzˈɪbɪɾᵻd kˈɛmɪkəl pɹˈɑːpɚɾiz əvən ˈælkəlˌaɪ mˈɛɾəl sˈʌtʃ ɐz kˌɑːpɹɪsˈɪpᵻtˌeɪɾɪŋ wɪð sˈiːsiəm sˈɔlts, wˌɪtʃ lˈɛd pˈɛɹi tə bᵻlˈiːv ðˌɐɾɪt wʌz ˈɛlɪmənt ˈeɪɾi sˈɛvən, kˈɔːzd baɪ ðɪ ˈælfə dᵻkˈeɪ ʌv æktˈɪniəm tˈuːhˈʌndɹɪd twˈɛnti sˈɛvən.