Crystal Structure of Regularly Th‐Symmetric [U(NO3)6]2− Salts with Hydrogen Bond Polymers of Diamide Building Blocks

Hexanitratouranate(IV), U(NO₃)₆]^2?, has been crystallized with anhydrous H⁺‐involving hydrogen bond polymers connected by selected diamide building blocks. Thanks to the significant moderation of electrostatic interactions between the anions and cations, the molecular structure of U(NO₃)₆]^2? in these compounds is regularly T_h‐symmetric. The f–f transitions stemming from 5f² configuration of U⁴⁺ are strictly forbidden by the Laporte selection rule in such a centrosymmetric system, so that the obtained compounds are nearly colourless in contrast to other U^IV species usually coloured in green.