The polyhalides are rather unstable, although those of rubidium and caesium are greatly stabilised by the feeble polarising power of these extremely large cations.
ðə pˌɑːlɪhəlˈaɪdz ɑːɹ ɹˈæðɚɹ ʌnstˈeɪbəl, ɔːlðˈoʊ ðoʊz ʌv ɹuːbˈɪdiəm ænd sˈiːsiəm ɑːɹ ɡɹˈeɪtli stˈeɪbəlˌaɪzd baɪ ðə fˈiːbəl pˈoʊlɚɹˌaɪzɪŋ pˈaʊɚɹ ʌv ðiːz ɛkstɹˈiːmli lˈɑːɹdʒ kˈæɾaɪənz.