or higher-order transition
in which the heat capacity
shows either a discontinuity (second-order) or a vertex (higher-order) at the transition
temperature. Example: The transition at
accompanied by a finite change in specific heat capacity
at constant pressure
of the low-temperature polymorph of quartz to the high-temperature polymorph.
PAC, 1994, 66, 577
(Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations
on page 584
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