Comments on the paper "Growth and optical studies of tris (thiourea) potassium barium sulphate crystal: a novel semiorganic NLO bimetallic crystal"

ABSTRACT

In a recent paper Azhar et al., (Mater. Res. Innov. https://doi.org/10.1080/14328917.2017.1392694) claim to have grown a tris (thiourea) potassium barium sulphate (TTPBS) crystal, which according to them is a novel NLO bimetallic crystal. In this comment, we prove that the so called TTPBS is a dubious crystal. In addition, we show that the so called barium thiourea chloride (Raju et al Mater. Res. Innov, 2016) thiourea barium chloride (Mahendra et al Optik 2017) and calcium bis(thiourea) chloride (Anis et al Optik 2016) single crystals are all dubious materials and do not contain any alkaline-earth metal but are simply thiourea.

KEYWORDS:

• Potassium sulphate
• barium sulphate
• tris (thiourea) potassium barium sulphate
• dubious crystal
• barium thiourea chloride
• thiourea barium chloride
• calcium bis(thiourea) chloride

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

¹ To avoid use of a strange code the title crystal is identified as compound 1 in this manuscript.

² Solubility data are taken from Wikipedia.