The antimonides are unstable and reactive as the Sb3− ion is a strong reducing agent; reaction of them with acids form the toxic and unstable gas stibine (SbH3).
ðɪ ˌæntɪmˈɑːnaɪdz ɑːɹ ʌnstˈeɪbəl ænd ɹɪˈæktɪv æz ðɪ ˌɛsbˈiː θɹˈiː mˈaɪnəs ˈaɪɑːn ɪz ɐ stɹˈɔŋ ɹᵻdˈuːsɪŋ ˈeɪdʒənt; ɹɪˈækʃən ʌv ðˌɛm wɪð ˈæsɪdz fˈɔːɹm ðə tˈɑːksɪk ænd ʌnstˈeɪbəl ɡˈæs stˈɪbaɪn ˌɛsbˈiː ˈeɪtʃ θɹˈiː.