Dipole-induced polymorphs of trans-2-hydroxycycloheptanecarboxylic acid with virtually the same unit cell

A. Kálmán, László Fábián, G. Argay, G. Bernáth, Zsuzsanna Gyarmati

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The polymorphs of trans-2-hydroxycycloheptanecarboxylic acid have exactly the same lattice parameters and thus mimic isomorphism. They differ only in their space group: Pna21 versus Pn21a. In form II, the screw axes turn the 18-membered rings of hydrogen-bonded tetramers around the b axis. In this way, the stacking of the layers becomes antiparallel, which cancels out the dipoles within the unit cell. In form I, the same turn around the c axis leaves the stacking of the layers parallel. Thus, the dipoles are canceled out by antiparallel domains in the crystals. Between the antiparallel domains of I, each frontier is a double layer of II. This implies that (a) a pure form of I cannot be isolated and (b) the percentage of II in I may alter from crystal to crystal.

Original languageEnglish
Pages (from-to)34-35
Number of pages2
JournalJournal of the American Chemical Society
Volume125
Issue number1
DOIs
Publication statusPublished - Jan 8 2003

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Polymorphism
Hydrogen
Crystals
Acids
Lattice constants

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  • Chemistry(all)

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Dipole-induced polymorphs of trans-2-hydroxycycloheptanecarboxylic acid with virtually the same unit cell. / Kálmán, A.; Fábián, László; Argay, G.; Bernáth, G.; Gyarmati, Zsuzsanna.

In: Journal of the American Chemical Society, Vol. 125, No. 1, 08.01.2003, p. 34-35.

Research output: Contribution to journalArticle

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