WebJul 16, 2024 · polymorphs of urea−barbituric acid (1:1) co-crystals were investigated to describe the dynamic character of their H-bond networks and to explain the … WebDec 27, 2024 · The inability to obtain a crystal form that has previously been reliably prepared is an important concern for industrial solid-state scientists. In the present study, we extend further the evidence that such a phenomenon also applies to cocrystals. Specifically, we report further on the apparent “disappearing polymorphs” of a cocrystal composed …
Disappearing polymorphs - Wikipedia
WebJun 1, 2015 · Nearly twenty years ago, Dunitz and Bernstein described a selection of intriguing cases of polymorphs that disappear. The inability to obtain a crystal form that … WebMay 16, 2024 · The inability to predict, control, and understand disappearing polymorphs remains a frustrating experience, even 25 … tithe crossword
Disappearing Polymorphs in Metal–Organic Framework Chemistry ...
WebJun 6, 2015 · Nearly twenty years ago, Dunitz and Bernstein described a selection of intriguing cases of polymorphs that disappear. The inability to obtain a crystal form that … WebAbstract. Polymorph screening is a crucial step in the characterization and development of pharmaceuticals. The 1998 recall of ritonavir upon the unexpected appearance of the more stable Form II polymorph remains a notorious case of disappearing polymorphs as the presence of Form II inhibited the ability to grow the original Form I. This study ... According to Ostwald's rule, usually less stable polymorphs crystallize before the stable form. The concept hinges on the idea that unstable polymorphs more closely resemble the state in solution, and thus are kinetically advantaged. The founding case of fibrous vs rhombic benzamide illustrates the case. Another example is provided by two polymorphs of titanium dioxide. Polymorphs have disparate stabilities. Some convert rapidly at room (or any) temperature. Mos… tithe crossword clue 4