3-Dodec-yloxy-2-hydr-oxy-N,N,N-trimethyl-propan-1-aminium bromide.

In the title compound, C(18)H(40)NO(2) (+)·Br(-), the ion pairs formed by the hydrogen-bonded bromide anions and organic cations are arranged into thick layers with the alkyl groups directed to the inside and the trimethyl-aminium groups and the bromide anions situated on the layer surface. The long alkyl chain in the cation adopts an all-trans conformation. In the crystal structure, molecules are connected by intermolecular O-H⋯Br hydrogen bonds, forming ionic pairs that are further connected into an extended chain structure via C-H⋯O hydrogen-bonding interactions. The crystal is chiral but nearly 90% of atoms in the unit cell are related by a pseudo-inversion center. The crystal shows racemic twinning with a 0.33:0.67 domain ratio.