Knoop microhardness anisotropy and Young’s modulus of l-arginine hydrochloride monohydrate and l-arginine hydrobromide monohydrate

Knoop microhardness anisotropy on the cleavage plane (100) of single crystals of l-arginine hydrochloride monohydrate (LAHCl) and l-arginine hydrobromide monohydrate (LAHBr) is reported. The microhardness increases from <001> to <011> and then decreases to <010> orientation. Calculation of Young’s modulus values for (100), (010), and (001) planes of LAHCl and LAHBr shows that the (100) plane for both crystals has the lowest value of Young’s modulus. Moreover, Young’s modulus values for all the planes of LAHCl are higher than those of LAHBr.