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Molecular Packing Modes. Part X. The Crystal and Molecular Structures of Trans, Trans ‐Muconic Acid
Author(s) -
Bernstein J.,
Leiserowitz L.
Publication year - 1972
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.197200058
Subject(s) - chemistry , muconic acid , molecule , crystallography , bond length , diffractometer , group (periodic table) , molecular geometry , crystal structure , crystal (programming language) , stereochemistry , benzene , organic chemistry , computer science , programming language
trans, trans ‐Muconic acid C 6 H 6 O 4 crystallises in the space group, with a = 8.982, b = 9.895, c = 3.787 Å, α = 103.68, β =75.27, γ = 101.58°, and two centrosymmetric molecules per unit cell. The structure was solved from 1671 reflections measured by an ω/2 θ scan with Mo K α radiation on an IBM 1800 computer‐controlled Siemens diffractometer, and refined anisotropically (on F 2 ) to R = 0.078. The geometries in the carbon chains of the two independent molecules are essentially identical; their bond lengths match to within 0.003 Å. The carboxyl group of one molecule is statistically disordered (C‐O 1.257, 1.275 Å) whereas in the second molecule the bond lengths differ significantly (1.236, 1.294 Å), indicating a greater degree of order. A careful consideration of the packing mode allows us to interpret the difference between the two molecules.