Polymorphism naming conventions

Polymorphs are usually named in the chronological order of their discovery and in general this has no bearing on their thermodynamic stability. Typical conventions are Form A, B, C.Form I, II, III..and Form a, P, y... 

There is no universally recognized system for the nomenclature of polymorphs. They are often labeled with Arabic (1, 2, 3,. . . ) or Roman (I, II, III, IV,. . . ) numerals, lowercase or uppercase Roman letters (a, b, c,. .. or A, B, C,. . . ) or lowercase Greek letters (a, (3, y,. . . ), or by names descriptive of properties (red form, low-temperature polymorph, metastable modification, etc.). If polymorphs are described by Roman numerals, it is a common convention to label the polymorph with the highest melting point with I, the one with the second highest with II, and so on. This notation vdll be used in this chapter. 

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