The low-temperature phase of morpholinium tetrafluoroborate

• Main Authors: Tadeusz Lis, Ryszard Jakubas, Przemyslaw Szklarz, Magdalena Owczarek
• Format: Article
• Language: English
• Published: International Union of Crystallography 2008-04-01
• Series: Acta Crystallographica Section E
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S1600536808004339

The crystal structure of the low-temperature form of the title compound, C4H10NO+·BF4−, was determined at 80 K. Two reversible phase transitions, at 158/158 and 124/126 K (heating/cooling), were detected by differential scanning calorimetry for this compound, and the sequence of phase transitions was subsequently confirmed by single-crystal X-ray diffraction experiments. The asymmetric unit at 80 K consists of three BF4− tetrahedral anions and three morpholinium cations (Z′ = 3). Hydrogen-bonded morpholinium cations form chains along the [100] direction. The BF4− anions are connected to these chains by N—H...F hydrogen bonds. In the crystal structure, two different layers perpendicular to the [001] direction can be distinguished, which differ in the geometry of the hydrogen bonds between cationic and anionic species.