Premium
Ab initio structure determination of m ‐toluidine by powder X‐ray diffraction
Author(s) -
Rukiah Mwaffak,
Lefebvre Jacques,
Descamps Marc,
Hemon Stephanie,
Dzyabchenko Alexander
Publication year - 2004
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889804006478
Subject(s) - crystallography , monoclinic crystal system , van der waals force , hydrogen bond , molecule , rietveld refinement , chemistry , metastability , powder diffraction , diffraction , lattice energy , crystal structure , van der waals radius , ab initio , x ray crystallography , bond length , physics , organic chemistry , optics
The powder X‐ray diffraction pattern of the crystalline phase of m ‐toluidine has been recorded with a sensitive curved detector (CPS120) at 150 K. The structure has been solved by real‐space methods (simulated annealing) followed by Rietveld refinements with phenyl rings as rigid bodies and with soft constraints on bond lengths for peripheral atoms. The cell is monoclinic with space group P 2 1 / c and Z = 8. Equivalent molecules form chains along c . The crystalline cohesion is achieved by N—H⋯N hydrogen bonds between neighbouring chains of non‐equivalent molecules and by van der Waals interactions of neighbouring chains of equivalent molecules. The hydrogen‐bonding network has been confirmed by lattice‐energy minimization. Anisotropic strain effects of the cell have been calculated. The directions of the minimal strains correspond to the directions of the hydrogen bonds. An explanation of the difficulty to crystallize the metastable phase is given.