Unique Surface HBs (IMAGE) National Institutes of Natural Sciences Caption Snapshots of unique hydrogen-bond (HB) structure derived from cooperative surface relaxation and fluctuation at the topmost surface layer of crystalline ice at ~160 K [T. Sugimoto et al., Phys. Rev. B. 99, 121402(R) (2019)]. Red, blue, and green lines represent 5-, 6-, and 7-membered rings (MRs), respectively. Credit NINS/IMS Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.