Single-crystal structure determination of psilocybin after dehydration

The crystal structure of the known low-temperature anhydrous phase of psilocybin {3-[2-(dimethylamino)ethyl]-1H-indol-4-yl dihydrogen phosphate, C₁₂H₁₇N₂O₄P} is reported. While the structure was previously characterized using powder X-ray diffraction, this study describes the first determination via single-crystal X-ray diffraction. High-resolution structural models were obtained both before and after in situ dehydration, allowing for a direct comparison of the lattice response to water loss.