Cover illustration: A view of the structure of strontium bis(hydrogen L-malate) hexahydrate. Displacement ellipsoids are drawn at the 50% probability level. See de Matos Gomes, Rodrigues, Costa, Nogueira & Belsley [Acta Cryst. (2006), C62, m416-m418].
The structural data at 163 and 293 K for II-BaB2O4, an excellent non-linear optical material, indicate a significant shortening of the c axial length in the unit cell at 163 K, whereas the a and b axial lengths essentially do not change.
The title compound crystallizes in P21/a with all the atoms located in general positions. The trichlate anion consists of pyramidal SO3 and CCl3 groups connected via an S—C bond in a staggered conformation with approximate C3v symmetry.