  The glycine sodium nitrite crystal reported by Khandpekar and Pati in the
paper entitled, Synthesis and characterisation of glycine sodium nitrite
crystals having non linear optical behaviour, Opt Commun 285, 2012 288-293 is
actually gamma-glycine. In addition, we show that glycine barium ammonium
nitrate, glycine sodium zinc sulfate, glycine barium calcium nitrate, glycine
acetamide and glycine dimer are dubious crystals.
