Structures and interconversion of polymorphs of 2, 3-dichloroquinizarin. Use of second harmonic generation to follow the change of a centrosymmetric to a polar …

RC Hall, IC Paul, DY Curtin

Index: Hall, Robert C.; Paul, Iain C.; Curtin, David Y. Journal of the American Chemical Society, 1988 , vol. 110, # 9 p. 2848 - 2854

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Citation Number: 15

Abstract

Abstract: 2, 3-Dichloroquinizarin has been found to exist in two crystalline forms. One, centrosymmetric, rearranges to the other (polar) on heating. The transformation can be followed by SHG as well as the more conventional methods of infrared spectroscopy and DSC. Crystal structures of both polymorphs have been determined. The first is in space group P2,/c with a= 12.309 (4) A, b= 5.089 (2) A, c= 22.690 (5) A,/3= 122.53 (3) O, Z= 4. ...