Calculated structures are reported for the mass-spectroscopically observed CAu22+ and CAu3+. Linear D-infinityh and D-3h geometries are obtained, respectively. The calculated properties of other multiply-bonded species, notably PtCPt, PtCCCPt and AuCCAu are reported. The Au+ and Pt function in these systems as chemical analogues to O. Further ligands are not needed for such 'autogenic isolobality'. (C) 2003 Elsevier B.V. All rights reserved.