Formation of Cerium Dioxide (image) Helmholtz Association Caption Ce(IV) dimers and trimers form in aqueous solution nanometer-sized cer dioxide crystals (CeO2). The size of the nanocrystals is in the order of two to three nanometers. Credit Atsushi Ikeda-Ohno Usage Restrictions None 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.