Melting free enthalpy diagrams

Free Enthalpy Diagram for Melting and Crystallization Under Ec uilibrium Conditions... 

Figure 7 Schematic diagram of the free enthalpy-temperature relationships for (o) orthorhombic, (h) hexagonal, and (m) melt phases. (From Ref. 85.)...

Fig. 9.2. Flowchart of prilocaine hydrochloride solid state forms and melt with transformation temperatures under ambient pressure conditions (left) and semi-schematic energy/temperature diagram of the polymorphs (right). Key H, enthalpy G, Gibbs free energy AHf, heat of fusion Liq, liquid phase (melt). Reproduced from [36]...

Schick s work includes the study of borides, carbides, nitrides, and oxides of some elements in Groups IIA, IIIB, IVA, IVB, VB, VIIB, and VIII as well as selected rare earths and actinides. As far as possible, the tables have been made compatible with the JANAF tables. Among the subjects treated are phase diagrams, heat capacities, enthalpies, entropies, enthalpies of phase transformation, formation, and reaction, melting temperatures, triple points, free energies of formation, vapour pressures, compositions of vapour species, ionization and appearance potentials, e.m.f. of cells, and enthalpies of solution and dilution. Volume 1 summarizes the techniques used to analyse data and cites the data analysed, and Volume 2 gives tables of values produced by this study. 

Figure 8.4 Energy diagrams showing H (melting enthalpy) and G(free energy) for enantiotropic polymorphism and the corresponding DSC curves To is the temperature of the transition A to B, 7 is the melting temperature of A and Tg is the melting temperature of B. DSC scans A, endothermic solid-solid transition into B and then B melts or A melts and eventually B crystallises from the melts. B is at room temperature and a spontaneous exothermic transition into A occurs or B melts.

Figure 2. Energy/temperature diagram for nimodipine. Form I has a melting point of 124°C, with heat of fusion of AH, . Form II has a melting point of 116°C and a heat of fusion of AH , n. The transition of Form I to Form II occurs at 88°C with a heat of transition of AHti n- The enthalpies are given by H, and H and the free energies by G j, G, and G, for the liquid and Forms I and II respectively. Reprinted from reference [18] with permission from Elsevier Science.

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