Classical Mechanical Methods for calculating Molecular Structure and Quantum Mechanical methods for calculating Molecular Electronic Properties are reviewed. Appropriate Theoretical Techniques are used to investigate drendritic molecules containing silicon (Si) made from 3,5-dihydroxybenzyl alcohol (DBHA), and tin (Sn) dendrimers made from 1,3,5 tri ethynyl benzene (TEB) as well as purely organic dendrimers of (TEB). Nanotubes formed from SMA (poly (styrene alt.maleic anhydride) [3] and from an imide derivative (SMI) [4] are considered. Finally the effect of water on the calcium carbonate CaCO3 Aragonite crystal (100) face is considered and contrasted with the effect of water on the (10.4) face of CaCO3 Calcite crystal.