‘bridging’ case the organic ammonium forms hydrogen bonds to two bridging and one apical atom (in the work of Mitzi, this is a halogen atom; in our work, oxygen) while in the ‘apical’ case hydrogen bonds are formed to two apical and one bridging atom (Figure \[fig:term\_bridg\]). This causes the alkyl chain to lie diagonally within the cell when the ammonium group is in a bridging configuration, but parallel for the apical. When the alkyl chain is longer than one carbon (methylamine), the second carbon in the chain would be too close to the opposing apical (oxygen) atom if a bridging conformation were adopted. Thus in general, apical bonding is observed for organic-inorganic systems with organic chain lengths of two or more carbon atoms.

![\[fig:term\_bridg\] Schematic diagrams illustrating the two bonding configurations, ‘bridging’ (left) and ‘apical’ (right), in organic-inorganic hybrid materials. Only the first carbon atom of the organic molecule is shown for simplicity.](bridg_term.eps){width="85mm"}

Given this, calculations were initially performed on the methylamine system in both the bridging and apical configurations, to compare the energies of each and as a starting point to construct the initial cells for the computations of the longer chain diamine hybrids. Figure \[fig:W-MA1\] shows the 