An X-Ray Structure Determination of the Twinned Crystals of Dinitrato-2,2′-dipyridylsilver(II)

The crystal structure of dinitrato-2,2′-dipyridylsilver(II) has been solved and refined to an R-value of 0.070. Four circle diffractometer measurements were obtained from the twinned triclinic crystals. The unit cell dimensions at 22 °C are: a = 697.5 ± 0.2 pm, b = 999.4 ± 0.2 pm, c = 1032.2 ± 0.2 pm, α = 113.46 ± 0.02°, β = 100.71 ± 0.02°, γ = 95.28 ± 0.02°. The space group is [Formula: see text] (No. 2) with two molecules per unit cell. The density is 2.06 ± 0.04 g cm−3 (measured), 2.02 g cm−3 (calculated). The four shortest bond lengths to silver are: Ag—O(1), 214.8 ± 1.5 pm; Ag—O(4), 213.6 ± 1.5 pm; Ag—N(1), 212.4 ± 1.6 pm; Ag—N(2), 220.7 ± 1.6 pm. These four bonds are distorted from square planar geometry with the silver atom lying 19.90 ± 0.17 pm out of the mean plane of the other four atoms. There are also long bonds to the nitrato groups of neighboring molecules: Ag—O(1′), 275.3 ± 1.3 pm; Ag—O(2″), 276.3 ± 1.6 pm. Inclusion of these bonds gives a distorted octahedral silver coordination. Though predominantly unidentate, there is a slight tendency toward bidentate bonding in both nitrato ligands: Ag—O(2), 305.8 ± 1.4 pm; Ag—O(5), 295.0 ± 1.7 pm. O(2) and O(5) approach the convex side of the distorted square planar coordination. The deviation from planarity of the closely bonded square, and angular distortions in the above mentioned octahedral coordination can be rationalized by considering the silver as eight coordinate. The bonds to silver may be grouped 4:2:2 by length or 4:3:1 by angular disposition.