DiscoveringPseudo-Supertetrahedral Functional Unitsin Salt-Inclusion Nonlinear Optical Material [Ba₂₂(SO₄)₅][Zn₁₄Ga₁₈S₅₈]

Chalcogenide supertetrahedral functional units play a vital role in both fundamental research and technological applications, but discovering new types of these units remains a significant challenge. This gap is largely due to the difficulty in inducing stable, novel supertetrahedral structures with unique properties. In this work, we successfully synthesize [Ba₂₂(SO₄)₅]­[Zn₁₄Ga₁₈S₅₈] (<b>BZGSO</b>), the first sulfate-incorporated salt-inclusion chalcogenide, using high-temperature solid-state methods. <b>BZGSO</b> features a unique, noncentrosymmetric FTW-type framework composed of unprecedented pseudosupertetrahedral [Zn₁₃Ga₁₆S₅₈] functional units. These units are formed by defective [Zn₃Ga₄S₁₆] clusters around a [ZnS₆] octahedron. Notably, <b>BZGSO</b> exhibits promising characteristics for infrared nonlinear optical applications. The theoretical analysis reveals key structure–property relationships, and a systematic study of X/Zn/Ga/S compounds suggests a trend in structural dimensionality based on [X/(Zn+Ga)] ratios. This work not only advances the understanding of supertetrahedral chemistry but also paves the way for the discovery of materials with potential technological applications.