Other solid solutions

Reference has already been made to the dehydration of alums (Sect. 1.2 and Table 10), decomposition of ammonium metal phosphates (Sect. 4.1.5) and the use of KMn04—KCIO4 solid solutions in mechanistic studies of the decomposition of potassium permanganate (Sect. 3.6). 

The dehydration of the double salt Na2Cas(S04)6 3 H20 obeyed [1290] the contracting area equation [eqn. (7), n = 2] and the Arrhenius parameters tended to increase with water vapour pressure from E = 75 kJ mole 1 and A = 9.2 X 103 s 1 at 0.013 N m 2 to 159 kJ mole 1 and 2.05 X 10I4s , respectively, at 2.6 kN m 2. This behaviour resembles that of hydrated calcium sulphate (Sect. 1.5.2) to which the reactant is closely related. 

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The tables in this section contain values of the enthalpy and Gibbs energy of formation, entropy, and heat capacity at 298.15 K (25°C). No values are given in these tables for metal alloys or other solid solutions, for fused salts, or for substances of undefined chemical composition. 

Although equilibrium was not established, it was more closely approached in the KCl-KBr-H20 system than in carbonate systems. For example, in a similar analysis of the strontianite-aragonite solid solution system (4 ), it was found that the experimental distribution coefficient for Sr substitution from seawater into aragonite is 12 times larger than the expected equilibrium value. Most of the distribution coefficients for the KCl-KBr-H20 system are within a factor of two of the equilibrium value, but clearly not at equilibrium. Considerable caution should be exercised before reaching the conclusion that equilibrium is established at relatively low temperatures in other solid solution-aqueous solution systems. 

The surface structure of CaHAP can be changed by substituting Ca2+ with other metal ions. Figure 6.2.9 shows the IR spectra of MgCaHAP solid solution particles (35). It is clearly seen that the surface P-OH bands vary as Ca2+ is replaced by Mg2+ the state of surface P-OH of MgCaHAP particles is affected by the kind of cations. Similar results were obtained on the other solid solution particles, such... 

Although the solubilities of some solid solutes—sucrose, to name just one example—are greatly affected by temperature changes, the solubilities of other solid solutes, such as sodium chloride, are only mildly affected, as Figure 7-20 shows. This difference has to do with a number of factors, including the strength of the chemical bonds in the solute molecules and the way those molecules are packed together. 

Compared with technical glasses the electrical resistivity of Zerodur is rather poor. The temperature for a resistivity of 10 Qcm is 178 °C. The dielectric constant e and the loss factor tan 5 at 1 MHz are 7.4 and 0.015, respectively. These data are not surprising. /3-eucryptite, a crystalline material with the special h-quartz s.s. composition Li20 AI2O3 2Si02, is known to be a good one-dimensional ion conductor [4.21], and due to the structure of h-quartz also other solid solution compositions are expected to behave similarly. So, neither the residual glass phase nor the crystalline phase are expected to block ionic conductivity effectively. 

Given that equation (28) is consistent with experiments performed in Manchester it is apparent from Fig. 6 that Q Q 2Si06 is rather less than Xgg j 2Si06 situation which is in marked contrast to all the other solid solutions discussed... 

LW interactions atoms and molecules at a solid surface can engage in the usual Lifshitz-van der Waals interactions with other solid, solute or liquid molecules in their reasonably close vicinity. 

AB interactions after satisfying all possible cohesive electron-acceptor/ electron-donor bonds in the solid, the only AB capacity still available for reacting at the solid siuface is that of the parameter that was present in the solid in excess. Thus only that monopolar capacity can be measured through its adhesive interaction with other solid, solute or liquid molecules of the opposite polarity. 

EL interactions exactly the same tuation occurs as in AB interactions, only atoms or molecules with the sign of charge that still is available after all cohesive EL bonds are satisfied, will be capable of engaging in adhesive EL interactions with other solid, solute or liquid molecules of the opposite sign of charge. 

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