Ab initio calculations have been carried out in a systematic investigation of pnicogen homodimers (PH2X)(2), for X = F, OH, NC, NH2, CCH, CN, CH3, H, and BH2. Complex binding energies range from 7 to 34 kJ mol(-1), which is within the range observed for neutral hydrogen-bonded complexes. One-bond spin-spin coupling constants across the pnicogen interaction (1p)J(P-P) exhibit a quadratic dependence on the P-P distance, similar to the dependence of (2h)J(X-Y) on the X-Y distance for complexes with X-H center dot center dot center dot Y hydrogen bonds. Thus, computed values of (1p)J(P-P) could be used to extract P-P distances from experimentally measured coupling constants. (C) 2011 Elsevier B.V. All rights reserved.