We study the interaction of N (OH)(3), P (OH)(3) and Sb (OH)(3) with a water molecule for which triply hydrogen-bonded complexes have been found. We obtain interaction energies and analyze the electronic density through Atoms-in-Molecules approach. Including the recent result for As (OH)(3), MP2 CBS extrapolated interaction energies are 9.37, 10.06, 10.67 and 10.72 kcal/mol for N (OH)(3), P (OH)(3), As (OH)(3) and Sb (OH)(3), respectively. CASSCF (6,6)+CASPT2 calculations reveal a multireference character for the complexes yielding interaction energies from 6.4 to 14 kcal/mol. AIM analysis shows three intermolecular bond critical points confirming the hydrogen bonds. NBO atomic charges show reveal the dominant dipole-dipole nature of the intermolecular interactions. (C) 2011 Elsevier B. V. All rights reserved.