decomposition

https://doi.org/10.1351/goldbook.D01547
The breakdown of a single phase into two or more phases. The term applies also to other chemical entities such as a normal molecule and a @R05171@.
Source:
PAC, 1994, 66, 577. (Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)) on page 580 [Terms] [Paper]