| Abstrakt: |
At room temperature, the title salt, C7H10NO+.Cl-, is orthorhombic, space group Pbca with Z' = 1, as previously reported [Zhao (2009). Acta Cryst. E65, o2378]. Between 250 and 200 K, there is a solid-state phase transition to a twinned monoclinic P21/c structure with Z' = 2. We report the high temperature structure at 250 K and the low-temperature structure at 100 K. In the low-temperature structure, the -NH3 hydrogen atoms are ordered and this group has a different orientation in each independent molecule, in keeping with optimizing N--H. . .Cl hydrogen bonding, some of which are bifurcated: these hydrogen bonds have N. . .Cl distances in the range 3.1201 (8)-3.4047 (8) A. In the single cation of the high-temperature structure, the NH hydrogen atoms are disordered into the average of the two low-temperature positions and the N. . .Cl hydrogen bond distances are in the range 3.1570 (15)-3.3323 (18) A. At both temperatures, the methoxy group is nearly coplanar with the rest of the molecule, with the C--C--O -- C torsion angles being -- 7.0(2)° at 250 K and --6.94 (12) and -- 9.35 (12)° at 100 K. In the extended orthorhombic structure, (001) hydrogen-bonded sheets occur; in the monoclinic structure, the sheets propagate in the (010) plane. [ABSTRACT FROM AUTHOR] |
