Acidic Centers on the Surface of a Crystalline α-Sn(IV) Phosphate Characterized by the Solid-State 1 H, 2 H, 31 P, and 119 Sn MAS NMR Techniques

A layered crystalline phosphate α-Sn(HPO ) ·H O ( ), prepared and characterized in the present study by the multinuclear solid-state nuclear magnetic resonance (NMR), powder X-ray diffraction, and thermogravimetric analysis techniques, was treated with D O and HOD imitating the reaction conditions in a water medium. The H solid-echo magic angle spinning NMR spectra of the products have revealed on their surface low mobile water molecules and hydronium ions, forming a structure close to the Zundel cation, [D O···D-OD ] . All the deuterons in the hydronium ions are tangled by hydrogen bonds with the water and the surface phosphate groups and stabilized by ionic interactions.