Fig. 2: Structural information.
From: Mechanically deformable organic ferroelectric crystal with plasticity optimized by fluorination
a Packing structure of PEA-MS viewed along b-axis with N − H···O hydrogen bonds (bule bonds). b-c Quasi 2D network layers of hydrogen bonds in the structure of PEA-MS (b) and PEA-TFMS (c). d Packing structure of PEA-TFMS viewed along c-axis with N − H···O hydrogen bonds (bule bonds) and C − H···F interactions (yellow bonds). e, f Packing structure of PEA-TFMS viewed along a-axis in ferroelectric phase (e) and paraelectric phase (f). The arrow in (e) represent the spontaneous polarization direction. The orange and green spheres in (f) represent highly disordered oxygen and fluorine atoms. g, h Equatorial plane projection of point group and spatial symmetry operations of space groups of ferroelectric phase (g) and paraelectric phase (h) for PEA-TFMS. Some hydrogen atoms were omitted for clarity. The red-blue-white surfaces in (a, d) represent the Hirshfeld surfaces of the PEA+ cations in the crystal structure, with the red points meaning hydrogen bonding interactions.
