Crystal Structure of Caesium Hydrogen (l)‐aspartate and an Overview of Crystalline Compounds of Aspartic Acid with Inorganic Constituents

The crystal structure of the new polar compound caesium hydrogen (L)‐aspartate, Cs(C4H6NO4), (abbreviated: Cs(L ‐AspH)) was determined from single crystal X‐ray diffraction data; it comprises two crystallographically different L ‐AspH anions that are connected via caesium cations to form a three dimensional framework. The Cs ions are irregularly sevenfold [Cs1O7] respectively eightfold [Cs2O8] coordinated to all α– and β– carboxylate oxygen atoms. Cs(L ‐AspH) represents a novel structure type of its own, as do most compounds of (L)‐aspartic acid with inorganic constituents. A brief summary of such structurally known aspartates is given. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)