Abstract Phenyl-, p-tolyl-and α-naphtyl-substituted disilanes react with gaseous or liquid HBr and HI to form the disilanes BrH 2 SiSiH 2 Br, IH 2 SiSiH 2 I, Br 3 SiSiH 3, I 3 SiSiH 3, Br 2 HSiSiHBr 2 and I 2 HSiSiHI 2. The syntheses and 20 Si-NMR spectra of the compounds are reported.