Comments on the paper "Insight on the growth and property studies of inorganic hydrated borate (Na sub(6)[B sub(4) O sub(5)(OH) sub(4)] sub(3).8H sub(2) O) single crystal - An effective third order nonlinear optical (NLO) material for optical limiting application"

Abstract

The authors of the title paper (Mater. Chem. Phy. 205 (2018) 138-146) claimed to have grown for the first time a new alkali metal borate with formula Na sub(6)[B sub(4) O sub(5)(OH) sub(4)] sub(3).8H sub(2) O (I) by slow evaporation of an aqueous solution containing NaOH, H sub(3) BO sub(3) and C sub(3) H sub(4) O sub(4) in 3:1:1 mol ratio. In this letter to the Editor, many points of criticism concerning the crystal growth, structure characterization and interpretation of the spectral and thermal data of I are described to prove that it is improperly characterized.