Porous crystals (IMAGE) Heidelberg University Caption In the background: light microscopy images of the single-crystal structures of the shape-persistent organic cage compound. In the front: ball-and-stick model of the single-crystal structure, grey: carbon, white: hydrogen, red: oxygen, blue: nitrogen, green: fluorine. Credit Prof. Dr. Michael Mastalerz Usage Restrictions This image may be used only in connection with the contents of this press release, and the source of the image must also be cited. License Original 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.