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

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. [ABSTRACT FROM AUTHOR]