Ba(dl-C4H4O5) — An alkaline earth metal-dicarboxylate hybrid crystal with the synergy of multi-bonds

Abstract

The organic–inorganic hybrid crystal, Ba(dl-C4H4O5), has been firstly prepared by hydrothermal method. It crystallizes in monoclinic crystal system with a centrosymmetric space group of P21/c with a=8.150(2) Å, b=10.447(3) Å, c=6.938(2) Å, β=95.599(3)° and Z=4. In this compound, the coexistence of organic ligand and the alkaline earth metal cation leads to the diversity of chemical bonds. The synergy of Ba–O ionic bonds and hydrogen bonds strengthens the crystal structure. Characterization of this earth metal-dicarboxylate hybrid crystal is described by using powder X-ray diffraction, infrared spectroscopy, UV–vis–NIR diffuse reflectance spectrum and the TG curve. In addition, Ba(dl-C4H4O5) possesses a short ultraviolet cutoff wavelength lower than 230nm determined by the electronic transition of C–O group, which signifies the potential use in UV region applications. And the electronic structure and optical properties are studied by first principle calculation method, which obtains a birefringence value of 0.04.