Structural hierarchy of NH$_{4}$V$_{3}$O$_{7}$ particles prepared under hydrothermal conditions

Despite having simple stoichiometry, NH$_{4}$V$_{3}$O$_{7}$ still remains an odd compound with poorly resolved structure among the series of known ammonium vanadates. Here, a new hydrothermal synthesis of the product with explicit NH$_{4}$V$_{3}$O$_{7}$ stoichiometry is evaluated. Intricate microstructure of the product is revealed as an aggregate of spherical microparticles consisting of microplatelets via scanning electron microscopy. To further guide the characterization of the NH$_{4}$V$_{3}$O$_{7}$ phase, X-ray diffraction analysis and first-principle calculations were carried out to refine the structure at an atomistic level and to predict electronic properties. The results suggest a complex structural hierarchy with consequent nanodomain organization of prepared NH$_{4}$V$_{3}$O$_{7}$ microplatelets.