Quantum chemical calculations have been performed to investigate the complexes of HMHXCCH, HMHXCF3, MHXCCH, and MHXCF3 (M = Be and Mg; X = Cl, Br, and I) at the MP2/aug-cc-pVTZ level. The geometrical, energetic, and spectroscopic parameters were analyzed for these complexes. The results show that the MH is a better electron donor in the halogen-hydride interaction than HMH. The enhancement of halogen-hydride interaction increases in the order of Cl < Br < I, Be < Mg, and XCCH < XCF3. The halogen-hydride interaction was understood with natural bond orbital, atoms in molecules, and electrostatic potentials. © 2012 Wiley Periodicals, Inc.