A new alkali-earth metal oxalatohydrophosphate crystal Ba2(C2O4)(HPO4): Synthesis, structure, optical and thermal properties

• Published in: Journal of alloys and compounds 2025-01, Vol.1010, p.177718, Article 177718
• Main Authors: Ji, Sen, Kang, Lei, Ma, Qingwen, Han, Yanyang, Liu, Shanshan, Liu, Ye, Yang, Xin, Feng, Kai
• Format: Article
• Language: English
• Subjects: Barium oxalatohydrophosphate; Birefringence; Crystal structure; Thermal analysis
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.177718

Single crystals of barium oxalatohydrophosphate Ba2(C2O4)(HPO4) were successfully synthesized by a simple solvothermal method for the first time. The crystal structure was determined from single-crystal X-ray diffraction (XRD). Ba2(C2O4)(HPO4) crystallizes in the monoclinic C2/m space group with unit cell parameters of a = 15.360(5) Å, b = 5.4418(18) Å, c = 8.969(4) Å, β = 100.48(3)°, and Z = 4. In the crystal structure of Ba2(C2O4)(HPO4), C2O4 groups are arranged in a completely consistent orientation. Therefore, Ba2(C2O4)(HPO4) shows a large birefringence of 0.097 at 550 nm. UV-Vis-NIR diffuse reflectance and theory calculation show that Ba2(C2O4)(HPO4) is a direct bandgap semiconductor with a bandgap of 4.33 eV. Fourier transform infra-red (FTIR) and Raman spectra confirm the crystal structure of Ba2(C2O4)(HPO4). [Display omitted] •The first alkali-earth metal oxalatohydrophosphate crystal Ba2(C2O4)(HPO4) was synthesized.•Ba2(C2O4)(HPO4) shows a large birefringence of 0.097 at 550 nm.•Ba2(C2O4)(HPO4) is an direct bandgap semiconductor with a bandgap of 4.33 eV.