Oriented Attachment Revisited: Does a Chemical Reaction Occur?

Abstract

Summary Oriented attachment (OA) growth has shown great significance in the development of crystal growth theory over the past decade, which is generally acknowledged as a physical process. Here, we report a different OA growth manner, which involves not only the physical nanoparticle attachment but also the chemical reaction between nanoparticles and ions. It is demonstrated that with the participation of NaHCO3 and NH4HCO3, micron-sized sheets of NaY(CO3)2·6H2O and (NH4)Y(CO3)2·H2O can be formed from Y2(CO3)3·2H2O nanoparticles through a chemical-reaction-directed OA. In contrast to the conventional OA process, this OA growth can produce single-crystalline substances whose crystallographic structures and chemical constituents are different (usually more complicated) from those of precursor nanoparticles. Such an OA mechanism shows applicability in a number of salts. Our findings not only extend the territory of the non-classical aggregation-based crystal growth mode but also provide a feasible approach for creating functional materials with complex architectures.