When it comes to crystals, we tend to imagine solid, rigid structures with distinct, repeating patterns, such as ice, salt, and quartz. However, new research conducted by Noushine Shahidzadeh, a physicist from the University of Amsterdam Institute of Physics, reveals a different reality: crystals can also be soft and pliable, lacking the recognizable facets that we typically associate with them.
The results of this research were recently published in the journal Nature Communications.
Crystals are generically hard solids and are usually identified by their well-defined geometrical shape that reflects the underlying highly ordered molecular structure. In their paper, the physicists show that surprisingly, some salts that contain water in their crystalline structure (so-called hydrated salts) can behave remarkably differently.
When these salts are slowly dissolved through contact with humid air, they become soft, deformable, and lose their facets. This is in contrast to regular crystals, which keep their faceted shape and stay hard while dissolving. Thus, the microcrystals that were studied simultaneously are crystalline in the bulk of the material but show liquid-like molecular mobility at their surfaces.
Reference: “Softness of hydrated salt crystals under deliquescence” by Rozeline Wijnhorst, Menno Demmenie, Etienne Jambon-Puillet, Freek Ariese, Daniel Bonn, and Noushine Shahidzadeh, 25 February 2023, Nature Communications.
The paper was selected by the editors of that journal as one of the featured articles for the Editors’ Highlights webpage of recent research in the section Materials science and chemistry. The Editors’ Highlights pages aim to showcase the 50 best papers recently published in an area.