Structural, Spectral, and Optical Characterization of Potassium bis(2-methyllactato)borate Hemihydrate Crystal

Abstract

Potassium bis(2-methyllactato)borate hemihydrate (KMB) was grown by a solvent evaporation technique. Crystal structural analysis revealed that the potassium cation was pseudo-octahedrally coordinated by five O atoms from four bis(2-methyllactato)borate (MB) ligands and half-occupied water. The sharp peaks in the powder x-ray diffraction (PXRD) pattern confirmed the perfect crystalline nature of the KMB. Transparency was observed in the range from 215 nm to 1100 nm, and the bandgap of KMB was determined to be 2.15 eV. The molecular structure of KMB was established by interpreting the functional group vibrations through vibrational spectroscopy. The molecular structure was further confirmed by the nuclear magnetic resonance (NMR) spectral technique. The peak followed by valley nature observed is due to the self-focusing behavior of KMB. The minimum transmission near the focus in the open aperture curve is attributed to the reverse saturation absorption nature of KMB. The third-order susceptibility (χ(3)) of KMB is estimated to be 4.17694 × 10−5 esu. These results suggest that KMB can be used in optical sensors as well as other photonic and optoelectronic applications.