Crystal structure of bis(allylammonium) oxalate

Abstract

The title salt, 2C3H8N+·C2O42−, crystallized with six independent allylammonium cations and three independent oxalate dianions in the asymmetric unit. One of the oxalate dianions is nearly planar [dihedral angle between CO2planes = 1.91 (19)°], while the other two are twisted with angles of 11.3 (3) and 26.09 (13)°. One cation has a synperiplanar (cis) conformation with an N—C—C—C torsion angle of 0.9 (3)°, whereas the five remaining cations are characterized bygauchearrangements, with the N—C—C—C torsion angles ranging from 115.9 (12) to 128.8 (3)°. One of the allylammonium cations is positionally disordered (fixed occupancy ratio = 0.45:0.55). In the crystal, the cations and anions are connected by a number of strong N—H...O and N—H...(O,O) hydrogen bonds, forming layers parallel to (001), with the vinyl groups protruding into the space between the layers.