Chemical reaction directed oriented attachment: from precursor particles to new substances

The oriented attachment (OA) of nanoparticles is an important mechanism for the synthesis of the crystals of inorganic functional materials, and the formation of natural minerals. For years it has been generally acknowledged that OA is a physical process, i.e., particle alignments and interface fusion via mass diffusion, not involving the formation of new substances. Hence, the obtained crystals maintain identical crystallographic structures and chemical constituents to those of the precursor particles. Here we report a chemical reaction directed OA growth, through which Y2(CO3)3.2H2O nanoparticles are converted to single-crystalline double-carbonates (e.g., NaY(CO3)2.6H2O). The dominant role of OA growth is supported by our first-principles calculations. Such a new OA mechanism enriches the aggregation-based crystal growth theory.