Scheme 2. Hypothesized Mechanisms for the Transformation of [β₂-SiW₁₁O₃₉]^8– into [γ-SiW₁₀O₃₆]^8–

Details: (i) The two-step mechanism first proposed by Kortz et al., which proceeds through a single {β-SiW₁₀} intermediate and (ii) an alternative three-step mechanism which involves an isomerization event between two {SiW₉} intermediate species. Solid lines highlight speciation/nucleation events, whereas dotted lines represent isomerization steps. Color code: W = teal, Si = orange, O = red. Gray polyhedra are used to differentiate W centers belonging to rotated {W₃} triads.