Hydrazonium(2+) hexafluorosilicate, N2H6SiF6: a NaCl-type structure with two-dimensional hydrogen-bonding networks

Abstract

Hydrazonium(2+) hexafluorosilicate, N2H6SiF6, 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 N2H62+ and SiF62− ions arranged in a NaCl-type packing and connected by hydrogen bonds to two-dimensional N2H6–SiF6 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 N2H6SiF6 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 N2H62+ ion, and to the tendency of this ion to form bent hydrogen bonds.