Fig. 3: Crystal structures of S-F.
From: Organic radical ferroelectric crystals with martensitic phase transition
a Packing views of S-F at LTP and HTP along the a-axis. Green arrow represents 21 screw axes. Blue dotted lines represent C–H…F interactions. b Partial schematic diagrams of TEMPO units at LTP and HTP. c Comparison of the cell lattices in the LTP (blue) and HTP (red). d Variation of unit cell parameters in the heating-cooling mode. Abrupt changes correspond to the phase transition. e Schematic diagrams of the distance and interaction energy between adjacent molecules at LTP and HTP. H atoms are partly omitted for clarity.
