allotropic transition

Synonym: allotriomorphic transition
https://doi.org/10.1351/goldbook.A00244
A transition of a pure element, at a defined temperature and pressure, from one crystal structure to another which contains the same atoms but which has different properties. Examples: The transition of @G02684@ to @D01671@, that of body-centred-cubic iron to face-centred-cubic iron, and the transition of orthorhombic sulfur to monoclinic sulfur. Synonymous with allotriomorphic transition.
Source:
PAC, 1994, 66, 577. (Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)) on page 579 [Terms] [Paper]