ABSTRACT
The third example reveals a special situation where methods based on thermodynamics are unable to discriminate between the forms while PXRD might be successful.
ThecompoundN-[2-{5-[(dimethylamino)methyl]-2-furanyl}thio]ethyl-N'-methyl-2-nitro-l,1ethenediamine hydrochloride exists in two isoenergetic crystalline forms. The forms give essentially the same solubility and melting point and thus cannot be discriminated by either solubility methods or calorimetry. PXRD was successful in discriminating between the two forms (Carstensen and Franchini, 1995).
