A wide pH-range stable crystalline framework based on the largest tin-oxysulfide cluster [Sn20O10S34].

We report, herein, a diamond-like oxysulfide framework, 3D-T4-SnOS, based on the largest supertetrahedral cluster of Sn4+ ions, i.e. [Sn20O10S34]. The framework remains intact in aqueous solution over a pH range between 1 and 14, and has a narrower optical bandgap, red-shifted fluorescence emission, and an enhanced photoelectric response compared to that of the smaller version, 2D-T3-SnOS, which has a building unit of supertetrahedral [Sn10O4S20].