The importance of the CO 2 2− anion in the mechanism of thermal decomposition of oxalates

Abstract

The effects of active (carbon dioxide and carbon monox{de) and neutral (helium, argon and nitrogen) atmospheres on the course of thermal decomposition of oxalates have been studied and compared. A mechanism of thermal decomposition has been proposed on the basis of the results obtained, the first stage of which consists in a heterolytic dissociation of the C~ bond, with the formation of carbon dioxide and the CO~-anion.In our earlier studies on the systematics of thermal decomposition mechanisms, it was shown that heterolytic cleavage is the first stage in the thermal decomposition of salts with bicentric anions containing a direct electron bond between the central atoms and a full coordination by oxide ligands (e.g. hyposulphates, $2062-, and hypophosphates, P20~-) [1, 2]: S2062-~SO3 + SO~-P20~ ~PO; +P033-Since carbon is an element of the previous period, oxalates are analogues of hyposulphates and hypophosphates and in the first stage they should decompose analogously:

Kinetic studies on the thermal decomposition of phosphate-doped sodium oxalate

“…Gorski and Kranicka [23] proposed that the decomposition in oxalates begins with the heterolytic dissociation of C-C bond forming CO 2 and CO 2 2-. In many cases, the C-C bond cleavage is the rate determining step [23].…”

“…Gorski and Kranicka [23] proposed that the decomposition in oxalates begins with the heterolytic dissociation of C-C bond forming CO 2 and CO 2 2-. In many cases, the C-C bond cleavage is the rate determining step [23]. The cleavage may be heterolytic to produce CO 2 and CO 2 2- [23] or homolytic to produce two CO 2 -anions [24].…”

“…In many cases, the C-C bond cleavage is the rate determining step [23]. The cleavage may be heterolytic to produce CO 2 and CO 2 2- [23] or homolytic to produce two CO 2 -anions [24]. In silver oxalate [25], the transfer of an electron from the C 2 O 4 2-to the cation is the first stage of the decomposition which leads to the rupture of the C-C bond [11].…”

Effect of addition of silver on the thermal decomposition kinetics of copper oxalate

“…Transition metal oxalates act as precursors for the synthesis of oxide nanoparticles, which have industrial uses and many analytical applications [1]. High-purity transition metal oxalates can be made by co-precipitation techniques, in which the metal ions are simultaneously precipitated in the expected stoichiometric proportions and provide the possibility of controlling the physical and chemical properties of the final products.…”

“…Thermal decomposition of metal oxalates is an important field of solid-state chemistry [1][2][3][4][5][6]. Transition metal oxalates act as precursors for the synthesis of oxide nanoparticles, which have industrial uses and many analytical applications [1].…”