ðɪs kˌɑːmpəzˈɪʃən ɐdˈɑːpts ðə flˈʊɹɹaɪt stɹˈʌktʃɚ, ænd ɪz tˈɜːmd ðə dˈɛltəfˈɔːɹm, ænd ˈoʊnli vˈɛɹi slˈoʊli θˈɜːməli dˌiːkəmpˈoʊzɪŋ æt ɹˈuːm tˈɛmpɹɪtʃɚɹ ʌntˈɪl ɐn ɐpɹˈɑːksɪmət kˌɑːmpəzˈɪʃən ʌv ɪz ɹˈiːtʃt, æt wˌɪtʃ pˈɔɪnt, ɪŋklˈuːʒənz ʌvðə hˈɛksɐɡənəl klˈoʊs pˈækt ˈælfəfˈɔːɹm, wˌɪtʃ ɪz ðə sˈeɪm fˈɔːɹm æz pjˈʊɹ taɪtˈeɪniəm, bɪɡˈɪn tʊ ɐpˈɪɹ.
This composition adopts the fluorite structure, and is termed the δ-form, and only very slowly thermally decomposing at room temperature until an approximate composition of  is reached, at which point, inclusions of the hexagonal close packed α-form, which is the same form as pure titanium, begin to appear.