Abstract The cooperativities for B⋯(HCl) 2 and B⋯(DCl) 2 complexes in solid argon are discussed. The cooperativities are much higher for the van der Waals complexes than for the medium-strong hydrogen bonds. The zero-point energy differences between the H- and D-bonds are calculated by the theory of Buckingham and Lin (A.D. Buckingham and F.C. Lin, Int. Rev. Phys. Chem., 1 (1981) 253). The results show that with the exception of the complexes involving the strong bases pyridine and pyridine N-oxide, the D-bonds are slightly stronger than their H counterparts. The difference between the D/H energies shows a tendency to decrease with increasing strength of the interaction. These conclusions agree qualitatively with data obtained from rotational spectroscopy (A.C. Legon and D.J. Millen, Chem. Phys. Lett., 147 (1988) 484).