Gilbert Lewis and the model of dative bonding

The electron-pair bonding model that was introduced by Gilbert Lewis 100 years ago is discussed in the light of modern quantum chemical methods for analysing the electronic structures of some simple molecules. It is argued that Lewis structures in conjunction with accurate quantum chemical calculations are still very useful for the description of chemical bonding. The emphasis lies on the difference between electron-sharing bonds A-B and dative bonds A→B which were suggested by Lewis as a general definition for acids and bases. The electronpair model, if combined with quantum chemical calculations, remains a powerful guide for the search of new molecules and for understanding molecular structures.