Discovery of Giant “Wine-Rack” Negative Linear Compressibility in Copper Cyanide

Jun 20, 2025
Structure of CuCN at 0.4 GPa (a) & (b) and at 6.4 GPa (c) & (d) viewed in the ac plane. Elongation along the a-axis under high pressure is observed due to the hinging of the wine-rack structure.
Structure of CuCN at 0.4 GPa (a) & (b) and at 6.4 GPa (c) & (d) viewed in the ac plane. Elongation along the a-axis under high pressure is observed due to the hinging of the wine-rack structure.

Copper cyanide (CuCN) has been discovered to exhibit giant negative linear compressibility (NLC), expanding along one crystalline axis under pressure - an extremely rare behavior.

Unlike other NLC materials that show either small NLC over a wide range or large NLC over a narrow range, CuCN shows large NLC over a wide pressure range, making it a unique material.

X-ray diffraction and Raman spectroscopy reveal that this unusual property arises from a remarkable "wine-rack" compression mechanism.

The discovery opens doors for advanced applications in pressure sensors, aerospace, seismic monitoring, and impact-resistant materials.

Authors

Russell Hemley (University of Illinois-Chicago)

Additional Materials

Designing Materials to Revolutionize and Engineer our Future (DMREF)