Does a “glycine magnesium chloride” crystal exist?

Abstract

The authors of a recently published paper (J Mol Struct 1277 (2023) 134,839) report to have newly grown seeds of “glycine magnesium chloride” (GMC) crystal by slow evaporation of an aqueous solution containing equimolar ratios of glycine and magnesium chloride. A critical analysis of the unit cell data and infrared spectrum of the so-called GMC crystal reveals the total absence of magnesium chloride, as these correspond to the γ-modification of glycine. In this letter to the Editor, we prove that all papers reporting on so-called GMC, “coumarin doped GMC” CDGMC, and “methylene blue dye doped GMC” MDGMC crystals, are erroneous as the material studied in all cases is γ-glycine. Hence, the quantum mechanical studies on the non-existent GMC, CDGMC and MDCMG crystals have no scientific value.