Disappearing and reappearing polymorphism in p-methylchalcone

Inna Barsky, Joel Bernstein, Peter W. Stephens, Kevin H. Stone, Eugene Cheung, Magali B. Hickey, Jan Olav Henck

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


One stable form (Form I) and two metastable forms (Forms II and IV) of p-methylchalcone have been obtained, with Form II having previously been reported to be a disappearing polymorph. To prevent the conversion of Form II, which has a melting point of 89-91°C, into the stable form it was produced in conditions free from seeds of the stable form. Form IV was discovered serendipitously as a single crystal that appeared in the preparation of a powder of Form II. Forms I and II have also been characterized by optical microscopy, differential scanning calorimetry (DSC), variable temperature powder X-ray diffraction, and spectroscopic analysis. The crystal structures of these three forms have been solved, Forms I and IV by single-crystal methods and Form II from synchrotron powder diffraction. This investigation highlights the fact that the challenges of reproducing experimental results (i.e., the production of a particular crystal form) may be overcome by a systematic search for new conditions under which previously obtained results can be regained.

Original languageEnglish
Pages (from-to)63-70
Number of pages8
JournalCrystal Growth and Design
Issue number1
StatePublished - 1 Jan 2008

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics


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