Molten electrostrictive volume

The electrostriction volumes have been found to be proportional to the number of water molecules per formula unit Agi F = (3.3 0.3) for the 21 molten salt hydrates for which there are data, Fig. 5.1. Therefore, the molar volumes F and the densities of molten salt hydrates CpA, H20 at their corresponding... 

Fig. 5.1 The electrostrictive volume decrease, Aei F, of hydrated molten salts plotted against , the number of water molecules in the hydrate, Eq. (5.3).

Fig. 33. Schematic representation of the effects of pressure on oligomeric proteins a) native dimeric protein with cavities/voids b) dissociation of the oligomer, hydration with electrostriction of polar/ionic groups, hydrophobic hydration of unpolar groups (-CR), release of void volume c) weakening of hydrophobic interactions provides pathways for water to penetrate into the interior of the protein, swelling of the core - molten-globule like state d) unfolding of subunits, disruption of the secondary/tertiary structure (hydration of residues not plotted here), loss of cavity volume within protein (adopted from ref. 139).

Another method for the estimation of the intrinsic volumes of electrolytes, independent of values of the ionic radii, was proposed by Pedersen et al. [53], who employed the molar volume of the molten alkali metal halides, extrapolated to ambient temperatures, as a measure of their intrinsic volumes in aqueous solutions, but the extrapolation is quite long. A variant of this idea is to use the molar volumes of molten hydrated salts, proposed by Marcus [54], where the temperature extrapolation to 25°C is much shorter. It is then necessary to subtract the volume of the water of hydration, which is n times the molar volume of electrostricted water, 15.2 cm mok at 25°C [55], from the extrapolated molar volume of the undercooled molten hydrated salt containing n water molecules per formula unit of the salt. A cogent method, applicable to highly soluble salts, was proposed by Marcus [56]. The volumes considered, applied to aqueous solutions, are intrinsic, so they should be independent of the concentration c and to a certain extent also of the temperature T. The partial molar volume of an electrolyte, V c, T), describes the volume that it actually occupies in the solution and does not include the volume of the water. Therefore, a fairly short extrapolation of the hnear 25°C) from c = 3M to such high concentrations at which all of the solvent is as closely packed as possible (completely electrostricted) is equivalent to considering the electrolyte as an undercooled molten hydrated salt... 

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See also in sourсe #XX -- [ , ]

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