Illustration (IMAGE) Heidelberg University Caption Changes to the natural tetrahedral structure of silicon (top left) in an unusual square planar geometry (bottom right). Credit Illustration: Ebner/Greb (Heidelberg) 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 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.