A theoretical calculation has been performed for the ternary complexes XCl∙∙∙FH∙∙∙F⁻ (X = CCH, CN, OH, NC, and F) and the corresponding binary complexes. The halogen bond in the dyad is very weak with the interaction energy less than 2.5 kcal/mol. Interestingly, the halogen bond gets a big enhancement when it combines with a very strong hydrogen bond in FH∙∙∙F⁻, and the largest interaction energy is up to ∼25.6 kcal/mol in FCl∙∙∙FH∙∙∙F⁻. The enhancement of halogen bond not only results in a larger elongation of X–Cl bond and a bigger redshift of the bond stretch vibration but also makes the blue-shifting halogen bond in NCCl∙∙∙FH be a red-shifting one in NCCl∙∙∙FH∙∙∙F⁻. The halogen bond belongs to a purely close-shell interaction in the dyad, while it becomes a partially covalent interaction in XCl∙∙∙FH∙∙∙F⁻ (X = OH, NC, and F) with negative energy density. In FH∙∙∙F⁻, the proton is shared between the two F atoms, however, this proton transfers towards the F⁻ end in XCl∙∙∙FH∙∙∙F⁻.

对三元络合物XCl∙∙∙FH∙∙∙F ⁻（X = CCH，CN，OH，NC和F）和相应的二元络合物进行了理论计算。二元体中的卤素键非常弱，相互作用能小于2.5 kcal / mol。有趣的是，卤键得到一个很大的提高，当它与在FH∙∙∙F A非常强的氢键结合^- ，和最大的相互作用能达到~25.6千卡/摩尔在FCL∙∙∙FH∙∙∙˚F ^-。卤素键的增强不仅导致X–Cl键的伸长更大，并且键的拉伸振动更大，而且使NCCl∙∙∙FH中蓝移的卤素键成为NCCl∙中的红移∙∙FH∙∙∙F ⁻。卤素键在二元组中属于纯闭壳相互作用，而在XCl∙∙∙FH∙∙∙F ⁻（X = OH，NC和F）中以负能量密度变为部分共价相互作用。在FH∙∙∙F ^−中，质子在两个F原子之间共享，但是，该质子在XCl∙∙∙∙FH∙∙∙F ^−中向F ⁻端转移。