Synthesis, structure and electrochemical properties of metal malonate Na2M(H2C3O4)2• nH2O (n=0, 2) compounds and comparison with oxalate Na2M2(C2O4)3•2H2O compounds

Oxalate and malonate based compounds were prepared by hydrothermal method. The crystal structure of oxalate compounds of formulae Na2M2(C2O4)(3)center dot 2H(2)O (with M = Mn, Fe, Co, Ni and Mg) was confirmed from single crystal diffraction. We report here a series of new malonate compounds Na2M(H2C3O4)(2)center dot 2H(2)O with M = Mn, Fe, Co, Ni, Zn and Mg, whose structure, thermal and electrochemical performances are presented. Metal malonate compounds crystallize in an orthorhombic structure built upon MO6 octahedra connected with malonate groups to form a layered structure. The removal/uptake of water from the malonate members was found to be reversible and the crystal structure of the anhydrous Na2Mn(H2C3O4)(2) is solved from powder diffraction and presents similarities with the hydrated phase. However, sodium 3d-metal oxalates/malonates compounds show poor electrochemical activity. (C) 2015 Elsevier Masson SAS. All rights reserved.