From the regular view which is perpendicular to (010) plane the distinguishment of such phases is challenging. However, some indications are present, visible as shear plane discrepancies (observed in Figure ). In conclusion, the grown W18O49 nanowhiskers were primarily composed of W18O49 lattice domains interspersed with tungsten suboxide phases possessing higher oxygen content. The notable presence of structural defects, corresponding with higher tungsten suboxides, could potentially be attributed to the reaction conditions. While the lowpressure hydrogen atmosphere is favorable for the vaporization of the oxide, it may be insufficient for the complete reduction of W VI to suboxides. . Two pairs of pentagonal columns and pentagonal channels are typical for W12O34 lattice and are isolated as square-like motifs in the WO3 phase observed in c). The lower part of the center figure is a pure lattice of the W18O49 with a typical pattern consisting of pentagonal columns (yellow pentagon in d) and hexagonal channels (marked blue in d). e) HRSTEM-HAADF measurement and associated nanodiffractions of selected phases W18O49 and WO3 on nanowhisker cross-section.