Thermal Properties and Crystal Structure of BaC4H4O6 Single Crystals

Single crystals of barium L-tartrate, BaC4H4O6, were grown at 308 K by a gel method using silica gel as the growth medium. Differential scanning calorimetry, thermogravimetric-differential thermal analysis, and X-ray diffraction measurements were performed on the single crystals. The space group symmetry (orthorhombic, P212121) and structural parameters were determined at room temperature. The crystal structure consisted of BaO9 polyhedra, C4H4O6 molecules, and zig-zag hydrogen-bonded chains along the a- and c-axes linked by O–H···O and C–H···O hydrogen bonds between adjacent molecules. Weight losses due to thermal decomposition of BaC4H4O6 occurred in the temperature range of 450–1530 K. We suggest that the evolution of 2H2, 2CO, CO, (1/2)O2, and O2 gases caused the observed weight losses and that the decomposition product, barium monocarbide BaC, formed a residue in the vessel.