Capturing the metastable state in the spontaneous and reversible single-crystal-to-single-crystal phase transition of riluzolium oxalate

Abstract

A spontaneous and reversible single-crystal-to-single-crystal (SCSC) polymorphic transition via a disordered state has been captured in a salt, riluzolium oxalate, with no categorical loss in the quality of the crystals. Variable-temperature powder X-ray diffraction (VTPXRD) experiments provide additional support for the observed SCSC transition. The conformational change, along with the more efficient packing at 100 K, is the driving force for the event.