The stability of the solid solution was examined using a series of diverse experimental conditions. Crystal structure effects were examined via X-ray diffraction (XRD) while more localized changes were revealed by attenuated total reflectance infrared spectroscopy (ATR-IR). Specifically, the internal vibrations of the phosphate group were used with the aim of detecting lithium rich and lithium poor phases. These two techniques corroborate to distinguish the metastable solid solution phase relative to the olivine and heterosite phases which emerge over time. Particles morphologies and size distribution were analysed by field-emission gun scanning electron microscopy (FEG-SEM) and dynamic light scattering (DLS) respectively. In addition, lithium content was confirmed by flame emission spectrometry (AES). The developed techniques and results relative to the solid solution metastability will serve as the basis for upcoming kinetics studies. These studies will rely on imposing a uniform reaction environment on the entire particle population, in contrast to kinetics derived from electrochemical analysis using composite electrodes.