Clusters from defect interactions

At higher defect concentrations, however, when substantial defect interactions are involved, the concept of point defects is mostly inadequate to explain nonstoichiometry. Large deviations from stoichiometry are accommodated by the formation of clusters of point defects and alternative models involve ordering of point defects to give rise to planar faults or new structural features, which eliminate point defects. 

Detailed studies about metal deposition from the gas phase onto SAMs have been published [108-110], The central question for the system substrate/SAM/deposit there (as well as in electrochemistry) is the exact location of the deposited metal On top of the SAM or underneath Three clearly different situations are easily foreseen (Fig. 31). (1) Metal on top of the SAM. Depending on a strong or weak chemical interaction between metal and SAM (e.g., functional end group of the SAM), the deposit will spread out on top of the SAM or it will cluster on the SAM. (2) Metal penetrating the SAM (e.g., at defects in the SAM) and connecting to the metal substrate underneath the SAM. This configuration is often pictured as a mushroom, with a thin connective neck and a large, bulky head. (3) Deposited metal is inserted be-... 

Fig. 4 Proposed defect cluster model in as-made zeolites with quaternary ammonium cations as structure directing agents (SDAs) hydrogen bond distances of 1.68 A are determined experimentally from the H NMR chemical shift of 10.2 ppm X and Y are atoms not further specified in the SDA the interaction between the SDA and the SiO- group is assumed based on bond valence arguments (see text)...

The thermodynamic functions of non-stoichiometric solids at very high deviations from stoichiometry are strongly affected by defect clusters and molecularities. The detailed theoretical description of the interactions between defects and the lattice as well... 

---