Preferred Label : polymorphic transition;
IUPAC definition : 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. Examples: ol li The transitions of SiO sub 2 /sub
(quartz-type) at 1143 K to SiO sub 2 /sub (tridymite-type), and at 1743 K to SiO
sub 2 /sub (cristobalite-type). /li li The transition of β-AgI (wurtzite-type
structure) to α-AgI (body-centred-cubic structure) at 418 K. Synonymous with enantiotropic
transition. /li /ol ;
Scope note : in a liquid-crystal transition, this term refers to phase changes in the smectic state
or columnar discotic state.;
Origin ID : P04748;
See also
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. Examples: ol li The transitions of SiO sub 2 /sub
(quartz-type) at 1143 K to SiO sub 2 /sub (tridymite-type), and at 1743 K to SiO
sub 2 /sub (cristobalite-type). /li li The transition of β-AgI (wurtzite-type
structure) to α-AgI (body-centred-cubic structure) at 418 K. Synonymous with enantiotropic
transition. /li /ol
