θɹˈiː dˈɪfɹənt stɹˈʌktʃɚz"pˈɑːlɪmˌoːɹfz"ɑːɹ nˈoʊn: jˈɛloʊ, ˈælfəɪn tˈuː z θɹˈiː hɐz ɐ dˈiːfɛkt kjˈuːbɪk stɹˈʌktʃɚ, ɹˈɛd bˈeɪɾəɪn tˈuː z θɹˈiː hɐz ɐ dˈiːfɛkt spˈɪnəl, tˈɛtɹɐɡənəl, stɹˈʌktʃɚ, ænd ɡˈæməɪn tˈuː z θɹˈiː hɐz ɐ lˈeɪɚd stɹˈʌktʃɚ.
Three different structures ("polymorphs") are known: yellow, α-In2S3 has a defect cubic structure, red β-In2S3 has a defect spinel, tetragonal, structure, and γ-In2S3 has a layered structure.