Na[GeF5]·2HF: the first quarternary phase in the H–Na–Ge–F system

• Published in: Acta crystallographica. Section C, Crystal structure communications Vol. 80; no. 8; pp. 401 - 406
• Main Authors: Bockmair, Valentin, Hoch, Constantin, Schusterbauer, Irina, Kornath, Andreas J.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01-08-2024; Wiley Subscription Services, Inc
• Subjects: Anions; Crystal structure; Fluorides; fluorine chemistry; Hydrogen fluoride; levelling effect; pentagonal bipyramidal coordination; Polyhedra; Research Papers; Sodium; sodium fluorogermanate; superacid; trans‐pentafluorogermanate; levelling effect; pentagonal bipyramidal coordination; superacid; crystal structure; fluorine chemistry; sodium fluorogermanate; trans-pentafluorogermanate
• ISSN: 2053-2296; 0108-2701; 2053-2296; 1600-5759
• DOI: 10.1107/S2053229624006338

The structure of cis‐ or trans‐bridged [GeF5]− anionic chains have been investigated [Mallouk et al. (1984). Inorg. Chem.23, 3160–3166] showing the first crystal structures of μ‐F‐bridged pentafluorogermanates. Herein, we report the second crystal structure of trans‐pentafluorogermanate anions present in the crystal structure of sodium trans‐pentafluorogermanate(IV) bis(hydrogen fluoride), Na[GeF5]·2HF. The crystal structure [orthorhombic Pca21, a = 12.3786 (3), b = 7.2189 (2), c = 11.4969 (3) Å and Z = 8] is built up from infinite chains of trans‐linked [GeF6]2− octahedra, extending along the b axis and spanning a network of pentagonal bipyramidal distorted Na‐centred polyhedra. These [NaF7] polyhedra are linked in a trans‐edge fashion via hydrogen fluoride molecules, in analogy to already known sodium hydrogen fluorides and potassium hydrogen fluorides.
trans‐Pentafluorogermanate dihydrogen fluoride represents the first quarternary phase in the system H–Na–Ge–F, and the third Na–Ge–F phase after the X‐ray structure analyses of Na2GeF6 and CsNaGeF6. The crystal structure of trans‐pentafluorogermanate dihydrogen fluoride consists of chains of [GeF6] octahedra and chains of pentagonal bipyramidal [NaF7] polyhedra. The Raman and IR spectra show the expected vibrational modes.