Crystal structure (IMAGE) Science China Press Caption Figure 1. Crystal structures. (a) [B5PO14F] fundamental building block of (NH4)3B11PO19F3. (b) Two dimensional [B5PO10F]∞ layers with 18-membered rings in the ab-plane of (NH4)3B11PO19F3. (c) Layer structure of KBe2BO3F2 viewed along the a-axis. (d) Crystal structure of (NH4)3B11PO19F3 viewed along the a-axis. Credit ©Science China Press Usage Restrictions Use with credit. 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.