The interaction energy and van der Waals intermolecule bond length of several structures of the CO-N-2 complex are calculated by the supermolecule CCSD(T) and MP4 methods using aug-cc-pVXZ (X = D,T,Q) basis sets extended by a set of midbond functions centered in the middle of the vdW bond. The most stable structures are found to be two distorted T-shaped configurations with the N atom pointing towards the C-O bond. This conclusion is compatible with the results of high-resolution infrared, microwave and millimeter studies. (C) 2002 Elsevier Science B.V. All rights reserved.