Amino­guanidinium(2+) amino­guanidinium(1+) hexa­chloro­antimonate(III) at 295 and 92 K

The crystal and molecular structure of the title compound, (CH₇N₄)(CH₈N₄)[SbCl₆], has been determined at 295 and 92 K. It is composed of isolated [SbCl₆]³⁻ octahedra and amino­guanidinium mono- and dications. One of four of the crystallographically inequivalent amino­guanidinium cations is disordered at both temperatures. Two crystallographically inequivalent [SbCl₆]³⁻ octahedra were found to possess three significantly longer Sb—Cl bonds than three other octahedra. The shorter bonds are in the range 2.456 (2)–2.577 (2) Å, whereas the longer ones are between 2.705 (2) and 2.931 (2) Å. Each short Sb—Cl bond is located trans to a long bond. It is argued that this deformation is caused by N—H⃛Cl hydrogen bonds.