Axial motion of water–hydrogen halide and water–halogen complexes in argon matrices

Abstract
The infrared spectra of the water (H2O,HDO,D2O) complexes with HCl, HBr, HI, Cl2, Br2 and I2 have been studied in argon matrices in the 11 to 25 K interval. In all cases, water acts as a lone‐pair donor. The hydrogen halide complexes are effectively planar and rotate around the axis through the heavy atoms. For the water halogen complexes, the results are less clear, but a similar rotation, coupled to low wave number bending motions, seems possible.