There are six structural effects that affect the stability, acidity/basicity, melting point,volatility and solubility of an organic compound. These are VAN DER VAALS, RESONANCE, H-BONDING, CH-HYPERCONJUGATION, STERIC EFFECT, and INDUCTIVE EFFECT. VAN DER WAALS is the attractive or repulsive forces between molecules (or between parts of the same molecule) other than those due to covalent bonds or to the electrostatic interaction of ions with one another or with neutral molecules. (source, wikipedia) RESONANCE is the delocalization of the PI bonds. This adds to the stability of the compound. H-BONDING or hydrogen bonding is the bonding of Hydrogen atoms to an electronegative atoms (i.e. O) H-bonding can be intramolecular or intermolecular. When a compound is capable of H-bonding, the forces of attraction involved is stronger. CH-hyperconjugation is also known as sigma-electron delocalization. The sigma electron delocalization takes place towards the sp2 hybridized atoms. STERIC EFFECT is the effect of BULKINESS in a molecule. INDUCTIVE EFFECT is when the electron cloud is DISTORTED: Towards the electronegative part of the molecule (electron-withdrawing) away from the electron repelling groups (electron-repelling)
