Polymorphism, polar morphology and absolute structure determination of 4-iodo-4′-nitrobiphenyl (INBP)

Pyroelectric and piezoelectric scanning microscopy applied to reveal the bipolar state of 4-iodo-4′-nitrobiphenyl (INBP)

“…The example we have selected for analysis is of fundamental interest: 4-iodo-49-nitrobiphenyl (INBP) shows polymorphism. 8 When crystallized from typical solvents at ambient temperature an orthorhombic, polar phase (Fdd2, mm2) is obtained. However, such crystals do not express unipolar symmetry.…”

“…Recent X-ray diffraction results 8 lead to the conclusion, that lamellar twinning is present, i.e. an intergrowth of Fdd2 and P2/c.…”

“…and P2 structures. 8 Crystals of the Fdd2 (mm2) structure were obtained by lowering the temperature of a solution (y80 uC to room temperature). The solvent dependent morphology expresses usually a non-polar shape 14 and shows a typical twinning ratio of about 69 : 31%.…”

“…The solvent dependent morphology expresses usually a non-polar shape 14 and shows a typical twinning ratio of about 69 : 31%. However, a hanging-drop procedure 8,15 has produced a mono-domain structure and a polar morphology. In this work we focused on bipyramidal single crystals (twinning ratio 69 : 31%) obtained by lowering the temperature of a 2-butanone solution.…”

Polar Vector Property of the Stationary State of Condensed Molecular Matter

“…If we exclude ionic systems (salts) to only consider neutral small molecules, there remain about 9% of the polar structures. Although twinning and disorder are currently addressed, we notice that only a small number of structural investigations have provided some knowledge on: (i) the absolute orientation of the polar axis in relation to the morphology [5][6][7][8][9][10][11][12]; and (ii) just in a few cases, the spatial distribution of the electrical polarization P el has been analyzed [13][14][15]. As a matter of fact, we do not know much about the polar domain states of (non-ferroelectric) molecular crystals.…”