Description:
<jats:p> Hydrazonium(2+) hexafluorosilicate, N<jats:sub>2</jats:sub>H<jats:sub>6</jats:sub>SiF<jats:sub>6</jats:sub>, at room temperature has an orthorhombic (Pbca, Z = 4), pseudotetragonal unit cell (a = 7.605(1) Å, b = 7.586(2) Å, c = 8.543(1) Å). The structure consists of centrosymmetric N<jats:sub>2</jats:sub>H<jats:sub>6</jats:sub><jats:sup>2+</jats:sup> and SiF<jats:sub>6</jats:sub><jats:sup>2−</jats:sup> ions arranged in a NaCl-type packing and connected by hydrogen bonds to two-dimensional N<jats:sub>2</jats:sub>H<jats:sub>6</jats:sub>–SiF<jats:sub>6</jats:sub> layers parallel to (001). All H atoms are engaged in hydrogen bonding. Four of the six [Formula: see text] bonds to each cation are normal but significantly bent; the other two are trifurcated, [Formula: see text], but the out-of-layer component of the trifurcated bond is relatively unimportant. The N<jats:sub>2</jats:sub>H<jats:sub>6</jats:sub>SiF<jats:sub>6</jats:sub> structure is compared in some detail with the structures of other hydrazonium(2+) salts, with particular attention to the N—N bond length, to the "effective" size of the N<jats:sub>2</jats:sub>H<jats:sub>6</jats:sub><jats:sup>2+</jats:sup> ion, and to the tendency of this ion to form bent hydrogen bonds. </jats:p>