A general strategy for colloidal stable ultrasmall amorphous mineral clusters in organic solvents

Abstract

While nature exerts precise control over the size and chemical composition of minerals, this is still a challenging task for artificial syntheses. Despite its significance, until now, there are still no reports on colloidal mineral nanoparticles in the subnanometer range. Here we developed a general gas diffusion strategy using 10,12-pentacosadiynoic acid as a ligand and ethanol as a solvent to fabricate stable amorphous mineral clusters with a core size of less than 2 nm. First discovered for CaCO₃, the method was successfully extended to produce monolayer protected clusters of MgCO₃, SrCO₃, Eu₂(CO₃)₃, Tb₂(CO₃)₃, Ce₂(CO₃)₃, Ca_x(PO₄)_y, CaC₂O₄ and their hybrid minerals, Ca_xMg_y(CO₃)_z and Ca_x(CO₃)_y(PO₄)_z. All the mineral clusters can be well dispersed in organic solvents like toluene, and are stable for a long period without further crystallization. Our work paves a way for the artificial synthesis of colloidal mineral clusters, which may have various uses in both fundamental research and industry.