Comments on the paper: ‘Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for l-aspartic acid nickel chloride single crystal’.

We argue that the ‘ L -aspartic acid nickel chloride’ crystal reported by the authors of the title paper (Optics Communications, 291 (2013) 304–308) is actually the well-known diaqua( L -aspartato)nickel(II) hydrate crystal. [ABSTRACT FROM AUTHOR]