A transition of a crystalline structure into one or more forms which differ in the
way identical layers of atoms are stacked. Example:
ZnS consists of two identical close packings,
one of
Zn atoms, the other
S atoms, with the one displaced to the other along the
c-axis through one-quarter of the layer spacing. In sphalerite-type
ZnS the layers have the face-centred-cubic (ABC ABC)
sequence,
in wurtzite-type
ZnS they have the hexagonal-close-packed
(AB AB)
sequence. The transition of sphalerite-type
ZnS to wurtzite-type
ZnS occurs at
.
Source:
PAC, 1994, 66, 577
(Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations
1994))
on page 589