Iceberg formations

Fig. 17. Model of the clathrate structure of the water in clathrates I. The centre of the hole is occupied by hydrophobic guest molecules in gas-hydrates (model of the iceberg formation in aqueous solution )...

In my work on aqueous solutions of inert gases, I have reformulated the iceberg-formation idea. Instead of claiming that argon forms icebergs, I started from the assumption that structure, any structure for that matter, is already there in the pure liquid. Argon does not form any new structure but rather only... 

Before embarking on a discussion of the arguments in favor of the H(pl effects, I would like to discuss another myth that has been propagating in the literature ever since Frank and Evans published their classic article in 1945. This myth concerns the explanation of the HcpO in terms of the pictorial idea of iceberg formation. The essence of this explanation may be summarized by the following reasoning ... 

Assertions (i) to (iv) are correct. Therefore, one concludes that iceberg formation is responsible for the large positive AG, i.e. iceberg formation explains the low solubility of s. As we have seen in this and the previous chapter, this conclusion is incorrect. The roots of this erroneous conclusion are to be found in the Frank and Evans article published in 1945. This article followed two preceding articles written by Frank (Frank, 1945). 

Frank and Evans went a step further. Immediately after discussing the idea of iceberg formation they wrote ... 

The assumption of iceberg formation gives a pictorial interpretation for the observation of Butler that the insolubility of non-polar substances in water is an entropy, rather an energy phenomenon. ... 

True, the low solubility of the inert gases in water is determined by the entropy of solvation and not by the enthalpy of solvation. However, whatever the iceberg formation contributes to the solvation entropy cannot affect the solvation Gibbs energy. Hence, the iceberg formation cannot be used to explain the low solubility. Finally, it is worthwhile mentioning that Frank and Evans were well aware of the speculative nature of their ideas about iceberg formation ... 

It seems quite strange to me that, in spite of the fact that the exact entropy-enthalpy compensation theorem has been in the literature for over 30 years, authors still use the iceberg formation argument to explain the hydrophobic effect. I would add one more quotation to demonstrate how respected authors still invoke the iceberg formation to explain the H0O effect, ignoring the entropy-enthalpy compensation theorem. In a very recent book, Tanford and Reynolds (2001) write (italics are mine) ... 

Shinoda, K., Kobayashi, M., and Yamaguchi, N., Effect of iceberg formation of water on the enthalpy and entropy of solution of paraffin chain compounds the effect of temperature on the critical micelle concentration of lithium perfluorooctane sulfonate, J. Phys. Chem., 91, 5292, 1987. 

X and a relatively large positive value of x This has been ascribed to iceberg formation of water molecules around the dissolved molecules, an exotermic reaction which leads to a decrease in entropy. In case of systems which actas strong acceptors in hydrogen bond formation one may also with aqueous solutions experience a LCST. 

The current interpretation of the hydrophobic effect is via iceberg formation, i.e., the tendency of water molecules around apolar molecules to cluster into molec-... 

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