ICYS, National Institute for Materials Science^* Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University, Skopje, Macedonia^** Department of Inorganic Chemistry, University of Zagreb, Zagreb, Croatia^*** Australian National University, Caberra, Australia^**** Department of Chemistry, University of Malaya, Malaysia^*****
○Pance Naumov^* Gligor Jovanovski^** Orhideja Grupce^** Branko Kaitner^*** David A. Rae^**** Seik Weng Ng^*****

The structure of the common artificial sweetener sodium saccharinate, with one of the largest unit cells for a small, nearly planar organic anion such as the saccharinate, was determined for the first time from laboratory X-ray diffraction data. The formally ¹⁵/₈ hydrate crystal is composed of 64 formula units and represents an eight-fold occupational and displacive modulation of a C2/m parent structure with 8 formula units. The lack of one water molecule in the hypothetical dihydrate crystal Na(C₇H₄NO₃S).2H₂O and the respective structural misfit result in eight-fold expansion of the aperiodicity and the formula Na₆₄(C₇H₄NO₃S)₆₄.120H₂O. Due to the extensive disorder, the compound can be considered a frozen intermediate state between complete disorder of a concentrated solution of the salt and the completely ordered triclinic Na(C₇H₄NO₃S).²/₃H₂O, which crystallizes as stable hydrate from ethanol.


Ref.: P. Naumov, G. Jovanovski, O. Grupce, B. Kaitner, A. D. Rae, S. W. Ng, Angew. Chem., Int. Ed. Engl. 2005, 44, 1251.