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Abstract

A new nomenclature for the crystalline phases present in a sequence of structural phase transitions occurring as a function of temperature and/or pressure is defined as a first step in presenting a unified and informative notation for the various phases appearing in a phase diagram. This nomenclature specifies in a compact but intuitive manner the essential crystallographic and physical characteristics of each phase in the sequence. The current label in common use for certain phases (e.g. $\alpha$, I, $\dots$), whenever such exists, is included in the new nomenclature. Eliminating confusion associated with the present multiple nomenclatures is expected to stimulate general use of the proposed new nomenclature. Examples of application to various types of solids are provided. Future extensions of the nomenclature are discussed.

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