Binary Phase Diagrams of Some Molecular Compounds—I

Abstract

Abstract The (i) anthracene-d-camphor, (ii) naphthalene-β-naphthol, (iii) anthracene-hexachlorobenzene and (iv) d-camphor-hexachlorobenzene phase diagrams have been determined by calorimetric measurements, optical microscopy and X-ray diffraction. The effect of the crystal symmetry, molecular volume and molecular shape of the component species on the extent of the terminal solid solutions is considered. In all systems the packing factor between the components is high (>0.92), but only in the case of naphthalene and β-naphthol are the molecules of similar shape. In this system a peritectic horizontal occurs at 367.3 K and extends from 42.5 to 72.5 mole pct β-naphthol, the limits of solubility at 298 K being 57.0 mole pct β-naphthol in naphthalene and 16.5 pct naphthalene in β-naphthol. The other three pairs of compounds form simple eutectics. In the anthracene-d-camphor system a eutectic point occurs at 81.5 mole pct camphor and 400.0 K and the limits of solid solubility at this temperature are 3 mole pct ...