Most routes to the pure alkali metals require the use of electrolysis due to their high reactivity; one of the few which does not is the pyrolysis of the corresponding alkali metal azide, which yields the metal for sodium, potassium, rubidium, and caesium and the nitride for lithium.
mˈoʊst ɹˈaʊts tə ðə pjˈʊɹ ˈælkəlˌaɪ mˈɛɾəlz ɹᵻkwˈaɪɚ ðə jˈuːs ʌv ᵻlɛktɹˈɑːləsˌɪs dˈuː tə ðɛɹ hˈaɪ ɹɪɐktˈɪvᵻɾi; wˈʌn ʌvðə fjˈuː wˌɪtʃ dʌznˌɑːt ɪz ðə pˌaɪɹoʊlˈaɪsiz ʌvðə kˌɔːɹɪspˈɑːndɪŋ ˈælkəlˌaɪ mˈɛɾəl ˈeɪzaɪd, wˌɪtʃ jˈiːldz ðə mˈɛɾəl fɔːɹ sˈoʊdiəm, pətˈæsiəm, ɹuːbˈɪdiəm, ænd sˈiːsiəm ænd ðə nˈaɪtɹaɪd fɔːɹ lˈɪθiəm.