Vapour growth, morphology, absolute structure and pyroelectric coefficient ofmeta-nitroaniline single crystals

Abstract

The growth speed of (hkl) faces in the vapour phase, the absolute structure obtained by X‐ray crystallography, and the value and the sign of the pyroelectric coefficient of meta‐nitroaniline (mNA) were analysed in detail. The in situ observation of morphologically well developed faces of several mNA crystals growing in evacuated ampoules reveals no pronounced growth speed anisotropy for polar faces defining the unique axis 2 of the mm2 group. Scanning pyroelectric microscopy confirms mono‐domain mNA crystals. X‐ray measurements in the space group Pca21 show that the molecular planes coincide with the {} and {} faces, and the nitro groups cover the {201} face in the opposite direction to the crystal tip, characterizing the polar habitus studied here. At room temperature, the sign of the pyroelectric coefficient is positive for a measured effective value of 6.3 µC m−2 K−1, in good agreement with values reported by other authors. From previous elastic and piezoelectric published data, the secondary pyroelectric effect was calculated to be positive and far greater than the effective one, yielding a negative value for the primary pyroelectric coefficient.

Crystal Growth of the Acentric Organic Nonlinear Optical Material Methyl-p-hydroxybenzoate: Morphological Variations in Crystals Grown by Physical Vapor Transport

“…Finally, it should also be pointed out that there still exist reports of limited growth on the apparently dead + c direction faces that need to be resolved. These include The two-dimensional growth of α-resorcinol from benzene solutions by Wells in the original paper on this matter − and the parallel similar growth of d,l -alanine from solution in water by Han et al The growth by 180° twinning of γ-glycine (S), α-resorcinol (S + V), , and MBANP (S) during growth from solution (S) and PVT (V). The recently reported two-dimensional growth of small (1 mm) methyl-4-nitroaniline crystals from the vapor phase by Hesterberg et al Inhibited directional growth of proteins …”

“…The recently reported two-dimensional growth of small (1 mm) methyl-4-nitroaniline crystals from the vapor phase by Hesterberg et al…”

“…• The two-dimensional growth of α-resorcinol from benzene solutions by Wells in the original paper on this matter 12−14 and the parallel similar growth of D,L-alanine from solution in water by Han et al 55 • The growth by 180°twinning of γ-glycine (S), 56 αresorcinol (S + V), 22,23 and MBANP (S) 10 during growth from solution (S) and PVT (V). • The recently reported two-dimensional growth of small (1 mm) methyl-4-nitroaniline crystals from the vapor phase by Hesterberg et al 57 • Inhibited directional growth of proteins. 58 All that can be said on these matters at present is that such growth has been ascribed to early growth at high supersaturations, 10,55 renucleation at the nongrowing surfaces, 10,22,56 or surface damage, 23 but this does not rule out other factors.…”