Structural transformation reactions from a metastable layered tellurte, Li₂Mo₃TeO₁₂ to stable polyoxometalates is disclosed using powder X-ray diffraction . The transformation reactions consist of four steps: substitution, decomposition, recombination, and precipitation. The key step of the reactions includes substitution of Li⁺ cations to larger alkali metal cations, K⁺, Rb⁺, and Cs⁺, which separates two-dimensional structural topologies consisting of MoO₆ and TeO₄ polyhedra. A unique structural feature of Li₂Mo₃TeO₁₂ is the presence of highly strained TeO₄ polyhedra, which imposes instability on the crystalline structure as well as the facile transformation. This new finding could provide an easy way to design novel functional metastable materials and to elucidate their transformation mechanisms.