Breakdown of the hydrogen bond strength-length analogy: a revision

A recent study which addressed the nature of the association between hydrog enoxalate anions in the solid state came to the conclusion that short OH .. . O contacts between these species did not constitute an attractive interac tion, but one which simply minimized inter-anion repulsion; in the light of new crystallographic evidence and a solution study, some issues raised in this work need to be re-evaluated.