Growth mechanism of octahedron-like BaMoO4 microcrystals processed in microwave-hydrothermal: Experimental observations and computational modeling

Octahedron-like BaMoO₄ microcrystals were synthesized by the co-precipitation method at room temperature and processed in microwave-hydrothermal at 413 K for different times (from 30 min to 5 h). These microcrystals were analyzed by X-ray diffraction (XRD), field-emission gun scanning electron microscopy (FEG-SEM) and transmission electron microscopy (TEM). XRD patterns showed that this material presents a tetragonal structure without the presence of deleterious phases. FEG-SEM and TEM micrographs revealed that the BaMoO₄ microcrystals present an octahedron-like morphology with agglomerate nature and polydisperse particle size distribution. These micrographs also indicated that the microcrystals grow along the 0 0 1] direction. The observed crystallographic planes in these structures were modeled computationally and a crystal growth model was proposed in order to explain the morphological changes as a function of processing time.