Polythermal solubility and complex thermal analysis of watersoluble trismalonate of light fullerene – C$_{60}$ [= C(COOH)$_{2}$]$_{3}$

The poly-thermal solubility of the tris-malonate C$_{60}$ [= C(COOH)$_{2}$]$_{3}$ – H$_{2}$O binary system was investigated from 20 – 80$^\circ$C with the help of the method of isotherm saturation in ampoules. Concentration of tris-malonate C$_{60}$ [= C(COOH)$_{2}$]$_{3}$ in solutions was determined by light absorption at 330 nm. A diagram of the solubility is non-monotonic, consisting of 2 branches, which correspond to 2 different crystal-hydrates of C$_{60}$ [= C(COOH)$_{2}$]$_{3}$ and one non-variant point, corresponding to the saturation both crystal-hydrates. Complex thermal analysis of C$_{60}$ [= C(COOH)$_{2}$]$_{3}$ crystal hydrates, in equilibrium with a saturated aqueous solution at room temperature, was performed from 20 – 600$^\circ$C. Consecutive effects of the losses of C=O and C=O + H$_{2}$O were determined.