Shape evolution of parallelogrammic magnesium oxalate controlled by phosphate species

Abstract

Phosphate species are capable of playing a crucial role in manipulating the shapes and properties of inorganic materials. Herein, we examined the shape evolution of magnesium oxalate dihydrate (MgC₂O₄·2H₂O) to parallelogrammic microparticles with sheet-like structure in a precipitation process under the influence of phosphate species in the form of sodium tripolyphosphate (Na₅P₃O₁₀). Supported by a series of time-dependent experiments, the shape evolution of MgC₂O₄·2H₂O was evidenced by the complexation and blocking effect of Na₅P₃O₁₀ via a later adsorption at the surface of the formed MgC₂O₄·2H₂O product. The results from scanning electron microscopy (SEM) images, energy dispersive spectroscopy (EDS) and X-ray photoelectron spectrometry (XPS) measurements show that the shape evolution of parallelogrammic particles is accompanied by a modification in the chemical composition via a later adsorption. Our results demonstrated that the amount of Na₅P₃O₁₀ participating into the self-assembly of the layer-like parallelogram varied with reaction time. In the initial reaction stage, little amount of Na₅P₃O₁₀ is involved in the particle formation, and the participating amount increased with extent of reaction. This investigation presents the effect of Na₅P₃O₁₀ on the self-assembly of MgC₂O₄·2H₂O particles with layer-like structure and highlights its role in the controllable synthesis of microparticles.