1961 年 81 巻 7 号 p. 960-963
Measurement of hydration of calcium pyruvate isonicotinoylhydrazone hydrate was carried out and examinations were made on the amount of water contained and mode of dehydration in three kinds of spindle, prismatic, and granular crystals (tentatively designated respectively as crystals A, B, and C). Dissociating vapor pressure of each hydrate was measured in the temperature range of 20-50°, and it was clarified that 2, 3, 6, and 7 moles of water were present in A crystal, 2, 4, and 5 moles in B crystal, and 2, 4, and 4.5 moles of water in C crystal. Empirical equation, log p=A-B/T was applied to the relationship between dissociating vapor pressure and temperature, constants A and B for each system were calculated, and kinetic constants (heat of dissociation ΔH, change of free energy ΔG, and entropy change ΔS) were calculated. Comparison of dissociating vapor pressure of each hydrate and average humidity in various points in Japan showed that heptahydrate of A crystal, pentahydrate of B crystal, and tetrahemihydrate of C crystal are the most stable against moisture.