Synthesis, characterization, Hirshfeld surface analysis and theoretical calculation of new organic–inorganic hybrid material: (C₄H₇N₂)₆[As₂W₁₈O₆₂]·4H₂O

New hybrid arsenotungstates based on Dawson polyanions [C₄H₇N₂]₆[As₂W₁₈O₆₂]·4H₂O (1) have been isolated by conventional solution method and characterized by single-crystal X-ray diffraction, infrared spectrum and UV–visible spectroscopies and thermogravimetric analysis. Hirshfeld surface analysis was performed to study the intermolecular interactions. Compound 1 crystallizes in hexagonal system, in a P-3 space group, with cell parameters a = 20.2904(2) Å, b = 20.2904(2) Å, c = 16.8246(2) Å, and a V = 5998.38(11) Å³. Compound 1 exhibits a three-dimensional chain constructed from Well–Dawson anions linked together with (C₄H₇N₂)⁺ cations and water molecules.