A transition in which a displacement of one or more kinds of atoms or ions in a crystal
structure changes the lengths and/or directions of bonds, without severing the primary
bonds. Examples: The transitions of the low-temperature polymorphs of
SiO2
(quartz, tridymite and cristobalite) to their respective high-temperature polymorphs,
which involve distortions or rotations of the
SiO4
tetrahedra. Also
Jahn–Teller and
ferroic transitions.
Source:
PAC, 1994, 66, 577
(Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations
1994))
on page 581