A particularly striking example of an alkalide is "inverse sodium hydride", H+Na− (both ions being complexed), as opposed to the usual sodium hydride, Na+H−: it is unstable in isolation, due to its high energy resulting from the displacement of two electrons from hydrogen to sodium, although several derivatives are predicted to be metastable or stable.
ɐ pɚtˈɪkjʊlɚli stɹˈaɪkɪŋ ɛɡzˈæmpəl əvən ˈælkəlˌaɪd ɪz "ɪnvˈɜːs sˈoʊdiəm hˈaɪdɹaɪd", ˈeɪtʃ plˈʌs nˈɑː mˈaɪnəs bˈoʊθ ˈaɪɑːnz bˌiːɪŋ kˈɑːmplɛkst, æz əpˈoʊzd tə ðə jˈuːʒuːəl sˈoʊdiəm hˈaɪdɹaɪd, nˈɑː plˈʌs ˈeɪtʃ mˈaɪnəs: ɪɾ ɪz ʌnstˈeɪbəl ɪn ˌaɪsəlˈeɪʃən, dˈuː tʊ ɪts hˈaɪ ˈɛnɚdʒi ɹɪzˈʌltɪŋ fɹʌmðə dɪsplˈeɪsmənt ʌv tˈuː ᵻlˈɛktɹɑːnz fɹʌm hˈaɪdɹədʒən tə sˈoʊdiəm, ɔːlðˈoʊ sˈɛvɹəl dᵻɹˈɪvətˌɪvz ɑːɹ pɹɪdˈɪktᵻd təbi mˌɛɾəstˈeɪbəl ɔːɹ stˈeɪbəl.