Na-superionic-conductor (NASICON) structured materials are considered as promising electrodes for sodium-ion batteries because of their 3D open-framework crystal structure, resulting in high cyclability and fast rate capability. Among them, Na3V2(PO4)3 has been extensively studied, showing satisfactory energy density and rate performance as well as good thermal stability. The crystal structure of Na3V2(PO4)3 is composed of repeating units called lanterns, into which two VO6 octahedra are joined together through three corner-sharing PO4 tetrahedra. Within the 3D framework generated by these lanterns, two crystallographic sodium sites, labeled Na (1) and Na (2), are usually reported. The Na (1) site is located between the lantern units along the [001]hexagonal direction and is surrounded by six oxygen atoms in its first coordination sphere and by six Na (2) atoms in its second one. At maximum, the Na(1) and Na(2) sites (of different multiplicities) can respectively generate one and three Na positions per formula unit, thus leading to the final stoichiometry Na4V2(PO4)3. During electrochemical reactions, although the Na(1) site is involved in the global Na-ion transport mechanism (Na(2) -Na(1) -Na(2) pathways), it tends to be almost fully occupied regardless of the total Na content into the material, whereas the Na(2) site is partially/fully emptied or filled depending on the compositions. It is well known that two Na + ions can be reversibly electrochemically extracted from a Na3V2(PO4)3 electrode, through a voltage-composition "plateau" at ~3.4 V (vs. Na + /Na) utilizing the V 4+/3+ redox couple (with a theoretical capacity of 117.6 mAh/g). The reaction has been described by many authors as a mechanism of two-phase reaction between Na3V2 3+ (PO4)3 and Na1V2 4+ (PO4)3. Additionally, one Na + ion can be inserted into Na3V2(PO4)3 at ~1.6 V (vs. Na + /Na) through the V 3+/2+ redox couple towards the Na4V2(PO4)3 composition (theoretical capacity of 58.8 mAh/g). Recently, Zakharkin et al. noticed the signature of an intermediate Na2V2(PO4)3 phase, which involves the V 4+/3+ redox couple. Nevertheless, no structural information on the intermediate phase was provided. Other previous reports also suggested the existence of Na2V2(PO4)3, but the authors barely contemplated the existence of a new intermediate phase. This suggests that the widely believed two-phase reaction between Na3V2(PO4)3 and Na1V2(PO4)3 needs to be reinvestigated, in particular, providing structural information and the origin of the appearance of the intermediate Na2V2(PO4)3 phase.