ɹˈiːniəm ɹˌoʊmən sˈɛvən ˈɑːksaɪd ɪz fˈɔːɹmd wɛn mətˈælɪk ɹˈiːniəm ɔːɹ ɪts ˈɑːksaɪdz ɔːɹ sˈʌlfaɪdz ɑːɹ ˈɑːksɪdˌaɪzd æɾ ɪn ˈɛɹ.
Rhenium(VII) oxide is formed when metallic rhenium or its oxides or sulfides are oxidized at  in air.