NanoYAG particles with spherical morphology have been synthesised using a solvothermal method; a structure sensitive reaction, where the chemical reaction and the particle growth kinetics are interdependent. It has been observed that the primary YAG particles agglomerated into similar to 30 nm clusters via a self-assembled Ostwald ripening process along (2 1 1) planes, separated by a distance of similar to 0.49 nm, at 270 degrees C and 2.0 MPa for 2h. These nanoclusters coalesced into single nanoparticles of similar to 30 nm in size and exhibited a smaller inter planar distance of similar to 0.26nm, corresponding to the (4 2 0) planes, when synthesized at 300 degrees C and 8.5 MPa for 2 h. in addition, the solvent 1,4-butanediol transformed into 1,4-diacetoxybutane, this will have undergone esterification by reacting with the terminal acetate groups cleaved from the precursor, yttrium acetate. The proposed mechanism based on the analytical evidence suggests that a complete dissolution of precursors facilitated the structural re-arrangement of atoms within the planes and lead to a significantly higher degree of crystallinity. Moreover, once the particles with (4 2 0) planes had formed, they were no longer involved in facile coalescence along their preferential planes due to their lower interfacial energy compared to the (2 1 1) planes. This led to control of the particle morphology and with little agglomeration occurring in the final nanopowder. (C) 2015 Elsevier B.V. All rights reserved.