The monatomic plumbide ion (Pb4−) is unknown, and indeed its formation is predicted to be energetically unfavourable; alkali metal plumbides have complex Zintl ions, such as .
ðə mˌɑːnɐtˈɑːmɪk plˈʌmbaɪd ˈaɪɑːn pˌiːbˈiː fˈoːɹ mˈaɪnəs ɪz ʌnnˈoʊn, ænd ˌɪndˈiːd ɪts fɔːɹmˈeɪʃən ɪz pɹɪdˈɪktᵻd təbi ˌɛnɚdʒˈɛɾɪkli ʌnfˈeɪvɚɹəbəl; ˈælkəlˌaɪ mˈɛɾəl plˈʌmbaɪdz hæv kˈɑːmplɛks zˈɪntəl ˈaɪɑːnz, sˈʌtʃ ɐz .