DEGREE OF MISCIBILITY BETWEEN NONISOMORPHOUS PLASTIC PHASES - BINARY-SYSTEM NPG (NEOPENTYL GLYCOL)-TRIS [TRIS(HYDROXYMETHYL)AMINOMETHANE]

The experimental phase diagram between the plastic crystals neopentyl glycol (NPG) and tris(hydroxymethyl)amino-methane (TRIS) has been established. The importance of the use of complementary techniques with different timescales in order to obtain the mast realistic phase diagram is underlined. The miscibility is discussed on the basis of the geometric conditions (size and shape of molecules and unit-cell dimensions) and of the role of the intermolecular interactions in the structure of the mixed crystals. Binary phase diagrams formed by related, previously reported neopentane derivatives are also analysed in the same manner.