The Protonation of Acetamide and Thioacetamide in Super­acidic Solutions: Crystal Structures of [H3CC(OH)NH2]+AsF6– and [H3CC(SH)NH2]+AsF6–

Acetamide and thioacetamide react with the superacid solutions HF/MF₅ (M = As, Sb) under formation of the corresponding salts [H₃CC(OH)NH₂]⁺MF₆^– and [H₃CC(SH)NH₂]⁺MF₆^– (M = As, Sb), respectively. The reaction of DF/AsF₅ with acetamide and thioacetamide lead to the corresponding deuterated salts [H₃CC(OD)ND₂]⁺AsF₆^– and [H₃CC(SD)ND₂]⁺AsF₆^–, respectively_. The salts are characterized by vibrational and NMR spectroscopy, and in the case of [H₃CC(OH)NH₂]⁺AsF₆^– and [H₃CC(SH)NH₂]⁺AsF₆^– also by single‐crystal X‐ray analyses. The [H₃CC(OH)NH₂]⁺AsF₆^– ( 1 ) salt crystallizes in the triclinic space group P$bar{1}$ with two formula units per unit cell, and the [H₃CC(SH)NH₂]⁺AsF₆^– ( 2 ) salt crystallizes in the monoclinic space group P2₁/c with four formula units per unit cell. In both crystal structures three‐dimensional networks are observed which are formed by intra‐ and intermolecular N–H ··· F and O–H ··· F or S–H ··· F hydrogen bonds, respectively. For the vibrational analyses, quantum chemically calculated spectra of the cations [H₃CC(OH)NH₂ · 3HF]⁺ and [H₃CC(SH)NH₂ · 2HF]⁺ are considered.