ɪnðə sˈɛkənd stˈɛp, ðɪ æmˈoʊniəm klˈoːɹaɪd sˈɔlt ɪz kənvˈɜːɾᵻd tə ðə tɹˈɪkloːɹˌaɪdz baɪ hˈiːɾɪŋ ɪn ɐ vˈækjuːm æt θɹˈiːhˈʌndɹɪd fˈɪfti dˈæʃ fˈoːɹhˈʌndɹɪd dᵻɡɹˈiːz sˈiː:
In the second step, the ammonium chloride salt is converted to the trichlorides by heating in a vacuum at 350-400 °C: