Wydział Chemii

Beata Bednarska-Bolek

J. Zaleski

Ryszard Jakubas

Grażyna Bator

2000

Journal of Molecular Structure

553

175-186

10.1016/S0022-2860(00)00577-9

Naukowa

Angielski

Artykuł

The results of the X-ray (at 295 and 355 K), dilatometric, differential scanning calorimetry and dielectric studies on a new piperidinium crystal, (C₅H₁₂N)₂SbCl₅, are presented. The anionic sublattice of the crystal is built up of infinite (SbCl₅²⁻)_n chains composed of SbCl₆³⁻ distorted octahedra connected with each other by corners. In voids of anionic sublattice two crystallographically independent piperidinium cations are located. At 295 K they are both in chair conformation. The compound undergoes three first-order phase transitions at 378.5 K (I→II), 339.5 K (II→III) and 205 K (III→IV). The mechanism of the (II→III) transition (Pna2₁→P2₁2₁2₁) was proposed based on the X-ray data. It is associated with changes in the conformation of the N(1) cation. In phase (III) its conformation changes to twist boat. The physical properties of this crystal are compared to those found for the other piperidinium crystals of the (C₅H₁₂N)₂MX₅ (M=Sb, Bi; X=Cl, Br) type.

Phase transition, Alkylammonium cations, X-ray diffraction, Differential scanning calorimetry, Dilatometric studies, Dielectric measurements

https://doi.org/10.1016/S0022-2860(00)00577-9

http://www.elsevier.com