Abstract:
Molecular frameworks — materials built like atomic scaffolding from metal nodes and molecular linkers1 — means we are now able to (attempt to) “design” materials with advanced properties. It’s found some properties arise due to the underlying framework topology, while others depend on the increasing complexity related to the introduction of molecular components, and in both cases responses can be an order of magnitude more extreme than those of conventional meaterials.2 A topical example is the large family of perovskite (or perovskite-like) materials and their varied properties: colossal magnetoresistance in mixed-valence manganites,3 large ferroelectric switching in metal–formate frameworks,4 lithium conductivity in Prussian blue analogues (PBAs),5 and high solar-conversion in lead-halide hybrid perovskites.6
An exciting area to exploit this chemical and mechanical flexibility is in “smart-responsive” technology, where a material is extremely sensitive simultaneously to a several external stimuli such as temperature, pressure, light, magnetic or electric field. Here we investigate the structures and properties of a series of cyanide and pseudo-cyanide materials with specific elastic instabilities at high pressure. These frameworks have been selected to have directionality “built in” — and therefore give rise to extreme and unusual responses at high pressure or temperature.
References
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