Spectroscopic inference on the structure of liquid ammonia

IR and Raman spectral data of liquid NH₃ and ND₂H are analysed. Spectroscopic evidence is in favour of extensive hydrogen bonding in the liquid. The number, frequencies and intensities of the transitions in the 3200–3500 cm^?1 region can be explained if cyclic dimers are the major species present in liquid NH₃. This hypothesis is compatible with the low viscosity and low boiling point of liquid NH₃.