The large and very weakly polarising alkali metal cations can stabilise large, aromatic, polarisable radical anions, such as the dark-green sodium naphthalenide, Na+[C10H8•]−, a strong reducing agent.
ðə lˈɑːɹdʒ ænd vˈɛɹi wˈiːkli pˈoʊlɚɹˌaɪzɪŋ ˈælkəlˌaɪ mˈɛɾəl kˈæɾaɪənz kæn stˈeɪbəlˌaɪz lˈɑːɹdʒ, ɚɹoʊmˈæɾɪk, pˈoʊlɚɹˌaɪzəbəl ɹˈædɪkəl ˈænaɪənz, sˈʌtʃ ɐz ðə dˈɑːɹkɡɹˈiːn sˈoʊdiəm nˈæfθeɪlnˌaɪd, nˈɑː plˈʌs sˈiː tˈɛn ˈeɪtʃ ˈeɪt mˈaɪnəs, ɐ stɹˈɔŋ ɹᵻdˈuːsɪŋ ˈeɪdʒənt.