A crystal – but not as we know it

When we think of crystals, we think of ice, kitchen salt, quartz, and so on – hard solids whose shapes show a regular pattern. Research performed in the group of UvA-IoP physicist Noushine Shahidzadeh shows that crystals can be quite different: they can be soft and deformable shapes without the familiar facets. The paper where these results were reported was featured as an Editor’s Highlight by the journal Nature Communications.

Floppy crystals

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, that 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.

Editors’ Highlight

The paper was published in Nature Communications and 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.

Publication

Softness of hydrated salt crystals under deliquescence, Rozeline Wijnhorst, Menno Demmenie, Etienne Jambon-Puillet, Freek Ariese, Daniel Bonn and Noushine Shahidzadeh. Nature Communications 14 (2023) 1090.

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