Giant negative linear compressibility in zinc dicyanoaurate

• Published in: Nature materials Vol. 12; no. 3; pp. 212 - 216
• Main Authors: Cairns, Andrew B., Catafesta, Jadna, Levelut, Claire, Rouquette, Jérôme, van der Lee, Arie, Peters, Lars, Thompson, Amber L., Dmitriev, Vladimir, Haines, Julien, Goodwin, Andrew L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2013; Nature Publishing Group
• Subjects: 639/301/1023; 639/301/1023/303; Actuators; Biomaterials; Compressibility; Condensed Matter; Condensed Matter Physics; Crystal structure; Helical; Hydrostatic pressure; letter; Materials Science; Mechanical properties; Muscles; Nanotechnology; Optical and Electronic Materials; Physics; Pressure sensors; Springs; Strain; Zinc; Mechanical properties
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat3551

The expansion of a material in one or more directions under increasing hydrostatic pressure is a phenomenon known as negative linear compressibility. The demonstration that zinc dicyanoaurate exhibits an unusually large negative linear compressibility opens up possibilities for designing other materials with comparable properties. The counterintuitive phenomenon of negative linear compressibility (NLC) is a highly desirable but rare property exploitable in the development of artificial muscles 1 , actuators 2 and next-generation pressure sensors 3 . In all cases, material performance is directly related to the magnitude of intrinsic NLC response. Here we show the molecular framework material zinc( II ) dicyanoaurate( I ), Zn[Au(CN) 2 ] 2 , exhibits the most extreme and persistent NLC behaviour yet reported: under increasing hydrostatic pressure its crystal structure expands in one direction at a rate that is an order of magnitude greater than both the typical contraction observed for common engineering materials 4 and also the anomalous expansion in established NLC candidates 3 . This extreme behaviour arises from the honeycomb-like structure of Zn[Au(CN) 2 ] 2 coupling volume reduction to uniaxial expansion 5 , and helical Au…Au ‘aurophilic’ interactions 6 accommodating abnormally large linear strains by functioning as supramolecular springs.