A NEW POLYMORPH OF METHIMAZOLE: SINGLE CRYSTAL AND POWDER X-RAY DIFFRACTION STUDY
O. A. Lodochnikova, A. V. Bodrov, A. F. Saifina, L. E. Nikitina, I. A. Litvinov
Keywords: methimazole, polymorphism, hydrogen bonds
Abstract
A new polymorph of 1-methyl-4-imidazoline-2-thione has been first discovered and studied by X-ray diffraction. The crystal of the new polymorph is monoclinic, the asymmetric part of the cell contains three independent molecules. In the crystal, the key compound is in the form of planar hydrogen-bonded dimers due to the interactions of the N–H…S type. The new modification is of an intensely yellow color in contrast to the previously known colorless forms, is characterized by a lower density but stronger hydrogen bonds; it is formed as a minor impurity to main triclinic polymorph.
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