Abstract
The two independent organic cations in the asymmetric unit of the chloromercurate(II) salt exhibit essentially the same features with almost planar pyridinium and dimethylamino groups. In the crystal, N—H⋯Cl and C—H⋯Cl hydrogen bonds as well as
π–π
and Cl⋯Cl interactions link the organic cations and inorganic anions into a three-dimensional network.
The title molecular salt, (C
7
H
11
N
2
)
2
[Hg
2
Cl
6
], crystallizes with two 4-(dimethylamino)pyridinium cations (
A
and
B
) and two half hexachloridodimercurate(II) anions in the asymmetric unit. The organic cations exhibit essentially the same features with an almost planar pyridyl ring (r.m.s. deviations of 0.0028 and 0.0109 Å), which forms an inclined dihedral angle with the dimethyamino group [3.06 (1) and 1.61 (1)°, respectively]. The dimethylamino groups in the two cations are planar, and the C—N bond lengths are shorter than that in 4-(dimethylamino)pyridine. In the crystal, mixed cation–anion layers lying parallel to the (010) plane are formed through N—H⋯Cl hydrogen bonds and adjacent layers are linked by C—H⋯Cl hydrogen bonds, forming a three-dimensional network. The analyses of the calculated Hirshfeld surfaces confirm the relevance of the above intermolecular interactions, but also serve to further differentiate the weaker intermolecular interactions formed by the organic cations and inorganic anions, such as π–π and Cl⋯Cl interactions. The powder XRD data confirms the phase purity of the crystalline sample. Furthermore, the vibrational absorption bands were identified by IR spectroscopy and the optical properties were studied by using optical UV–visible absorption spectroscopy.