1. (A) Optimized adsorption structures of HCHO with red, white and black balls representing O, H and C, respectively, on W₅ (HCHO-W₅ configuration) (a) and O₇ (HCOH-O₇ configuration) (b) sites of WO-terminated h-WO₃ (001) surface; (B) Calculated electron density difference of the clean (001) surface (a), HCHO-absorbed on (001) surface for HCHO-W₅ (b) and HCOH-O₇ (c) configurations^[59]

2. (A) Monoclinic structure (a) of W₁₈O₄₉ nanowires supercell model and its top views of NW1(b) and NW2(c), where NW1 and NW2 include largely cations W⁵⁺ and cations W⁶⁺, respectively; (B) Optimized models for NW1 (a) and NW2 (b), of W₁₈O₄₉ (010) nanowires^{[24, 61-62]}.

3. (a) Density of states and projected density of states of bulk WO₃ without oxygen vacancy, and (b) structure of WO₃(002) with one oxygen vacancy^[28]

4. (a) Geometrical optimized equilibrium configuration of WO_3-x/TiO_2-x with red, blue and white balls representing O, W and Ti, respectively, and (b) schematic diagram of the self-doping Ti³⁺, localized surface plasmon resonance (LSPR), and charge transfer in WO_3-x/TiO_2-x^[72]

5. Top view of the supercell of Ti-doped h-WO₃^[29]

6. Monolithically band-engineered WSe₂-MoS₂ p-n heterojunction^[82]

7. Crystal structures of Wadsley-Roth phases^[85]

8. Optimized sadsorption model of different gas molecules on W₁₈O₄₉ with blue, purple, red, gray and white balls represent W, Co, O, C and H, respectively^[86]

9. Various intercalating sites corresponding to different distances to the h-WO₃(100) surface with blue, red and purple balls representing W, O and cations, respectively^[90]

10. Lowest-energy structures of (WO₃)_n clusters (n=2-12) and several metastable isomers (labeled as 5b, 6b, 10b) with blue and red balls representing W and O, respectively^[95]