Does anyone know how this might be constructed in Tripos 5.2? In particular, we were hoping to construct electrostatically bound complexes involving a hydrogen bond between Cl3C-H and eg oxygen. But the partial charges on chloroform at -0.15 on the chlorine, +0.45 on the carbon, and zero on the hydrogen. The result is no real hydrogen bonding. Are we out of luck on this one? -- Henry Rzepa. +44 (020) 7594 5774 (Voice); +44 (0870) 132 3747 (eFax); rzepahs at mac.com (iChat) http://www.ch.ic.ac.uk/rzepa/ Dept. Chemistry, Imperial College London, SW7 2AZ, UK. (Voracious anti-spam filter in operation for received email. If expected reply not received, please phone/fax).