These are not the only phosphides and arsenides of the alkali metals: for example, potassium has nine different known phosphides, with formulae K3P, K4P3, K5P4, KP, K4P6, K3P7, K3P11, KP10.3, and KP15.
ðiːz ɑːɹ nˌɑːt ðɪ ˈoʊnli fˈɑːsfaɪdz ænd ˈɑːɹsənˌaɪdz ʌvðɪ ˈælkəlˌaɪ mˈɛɾəlz: fɔːɹ ɛɡzˈæmpəl, pətˈæsiəm hɐz nˈaɪn dˈɪfɹənt nˈoʊn fˈɑːsfaɪdz, wɪð fˈɔːɹmjʊlˌiː kˈeɪ θɹˈiː pˈiː, kˈeɪ fˈoːɹ pˈiː θɹˈiː, kˈeɪ fˈaɪv pˈiː fˈoːɹ, kˌeɪpˈiː, kˈeɪ fˈoːɹ pˈiː sˈɪks, kˈeɪ θɹˈiː pˈiː sˈɛvən, kˈeɪ θɹˈiː pˈiː ɪlˈɛvən, kˌeɪpˈiː tˈɛn.θɹˈiː, ænd kˌeɪpˈiː fˈɪftiːn.