A
reversible transition of a solid crystalline phase at a certain temperature and pressure (the
inversion point ) to another phase of the same chemical composition with a different crystal structure.
Note:
In a liquid-crystal transition, this term refers to phase changes in the
smectic state or columnar discotic state.
Examples:
-
The transitions of
SiO2
(quartz-type) at
to
SiO2
(tridymite-type), and at
to
SiO2
(cristobalite-type).
-
The transition of
β-AgI
(wurtzite-type structure) to
α-AgI
(body-centred-cubic structure) at
.
Synonymous with enantiotropic transition.
Source:
PAC, 1994, 66, 577
(Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations
1994))
on page 588
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
