Vibrational frequencies of gaseous Br2O and OBrO were observed using the Fourier transform infrared spectrometer. For the first time, bands at 629.0 cm(-1) (nu (3)) and 532.9 cm(-1) (nu (1)) were recorded for both Br-O asymmetric and symmetric stretching vibrations of gaseous Br2O. Two fundamental vibrations were observed at 798.7 cm(-1) (nu (1)) and 846.3 cm(-1) (nu (3)) for the (OBrO)-Br-18 radical. In addition, two new peaks at 2333 cm(-1) and 668 cm(-1) were observed in a HOBr spectrum. They are tentatively assigned to the H-Br and Br-O stretching vibrations of a HOBr isomer on the basis of ab initio computational results.