Unusual geometries in main group chemistry

Over the past twenty five years, numerous heteroatom-containing analogues of classical organic moieties have been prepared and structurally characterized. The incorporation of group 13 to 15 heteroelements has often been reported to induce significant geometric distortions compared to the corresponding carbon compounds. These unusual geometries in main group derivatives are examined in this tutorial review, and the precise role of the heteroelements is discussed.