Growth-induced incommensurability observed in the organic co-crystal hexamethylenetetramine resorcinol.
Co-crystals of hexamethylenetetramine and resorcinol were investigated by X-ray diffraction. The structure was refined in the superspace group Xmcm(0beta0)s0s, X=(1/2 1/2 0 1/2). In the average structure the resorcinol molecules are disordered between two orientations. The main effect of the modulation in the structure is a harmonic modulation of the occupation probabilities of the two orientations of the resorcinol molecule. However, the modulated order is not perfect and the resorcinol molecules remain partially disordered. Below 270 K the crystal undergoes a phase transition to a commensurately modulated structure with modulation vector q=(0 1/2 1/4) and superspace group X2/m(0betagamma)0s. The structure of the low-temperature phase could not be determined owing to the poor quality of the crystals affected by the reconstructive phase transition.
Rodriguez
Soraya Maria Belluga
SM
Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Cristallographie, BSP, CH-1015 Lausanne, Switzerland.
Palatinus
Lukás
L
Petrícek
Václav
V
Chapuis
Gervais
G
D003460:Crystallization; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008709:Methenamine / Q000737:chemistry*; D008958:Models, Molecular; D012118:Resorcinols / Q000737:chemistry*; D013696:Temperature
D012118:Resorcinols; D008709:Methenamine; C031389:resorcinol