Abstract

Manganese L-tartrate dihydrate, L-MnC₄H₄O₆·2H₂O, and manganese DL-tartrate dihydrate, DL-MnC₄H₄O₆·2H₂O, crystals were grown at room temperature by the gel method using silica gels as the growth medium. Differential scanning calorimetry, thermogravimetric-differential thermal analysis, and X-ray diffraction measurements were performed on both crystals. The space group symmetries (monoclinic P2₁ and P2/c) and structural parameters of the crystals were determined at room temperature. Both structures consisted of slightly distorted MnO₆ octahedra, C₄H₄O₆ and H₂O molecules, and O–H···O hydrogen-bonding frameworks between adjacent molecules. Weight losses due to thermal decomposition of the crystals were found to occur in the temperature range of 300–1150 K. We inferred that the weight losses were caused by the evaporation of bound 2H₂O molecules, and the evolutions of gases from C₄H₄O₄ and of (1/2)O₂ gas from MnO₂, and that the residual black substance left in the vessels after decomposition was manganese oxide (MnO).

This work is licensed under a Creative Commons Attribution 4.0 License.